The short answer is yes, and no. You can’t sign a prenup once you’re married because a prenup, by definition, is signed before marriage. But you can enter into a financial agreement during your marriage, or after it ends. In Australia, that document is commonly called a postnuptial agreement, though the correct legal term is a financial agreement.
That distinction matters more than it sounds. A postnuptial agreement is not simply a prenup with a different date on it. The circumstances are different, the pressures are different, and the legal framework that governs it is different. What you’re signing, why you’re signing it, and how it’s prepared all affect whether it will hold up when it counts.
Most people assume that because they missed the window before the wedding, they’ve lost the chance to formalise anything. That’s not true. But the opposite assumption, that any signed document will do the job, is just as dangerous.
Here’s what you need to know before you start.
Key Takeaways
- You can sign a financial agreement during your marriage. It is commonly called a postnuptial agreement, but the legal term in Australia is a financial agreement made under the Family Law Act 1975.
- A postnup is not a prenup signed late. The circumstances, requirements and legal provisions are different. Both require independent legal advice, but the context around a postnup is often more complex.
- De facto couples can also enter these agreements. The framework applies to de facto relationships as well as marriages.
- A postnuptial agreement covers property, debts, superannuation and spousal maintenance. It cannot determine where children will live or set child support payments.
- An agreement signed under pressure may be set aside. Courts have set aside financial agreements where one party lacked genuine independent advice, or where there was duress, undue influence or unconscionable conduct.
- If you are already separating, a postnuptial agreement may not be your best option. Consent orders or a negotiated property settlement may be more appropriate. Get advice on which process suits your situation before you commit to either.
Can you sign a prenup after you are married in Australia?
Technically, no. A prenuptial agreement is defined by timing: it is made before a marriage. Once you’re married, that window has closed.
What the law does allow is a financial agreement made during the marriage, under section 90C of the Family Law Act 1975. This is what most people mean when they search for a postnuptial agreement in Australia. If your marriage has already ended and you want to formalise arrangements after separation, there’s a separate provision for that too, under section 90D.
The practical result is that the door isn’t closed just because you’re already married. But the document you’re signing, the legal provisions that govern it, and the requirements for making it binding are specific to where you are in the relationship. Getting the right document for the right stage matters.
Key Point: “Postnuptial agreement” is the plain-English label most people use. The document your lawyer drafts is a financial agreement under the Family Law Act 1975. The informal name and the legal instrument are not the same thing, and knowing which section applies to your situation affects how the agreement is structured.
What is a postnuptial agreement in Australia?
A postnuptial agreement is a financial agreement between two married people, made during the marriage rather than before it.
It sets out how property, financial resources, superannuation interests and spousal maintenance will be dealt with if the relationship ends. It can be comprehensive or specific: some couples document every asset; others deal with one particular thing, such as an inheritance or a business.
What it is not is a parenting plan. It has nothing to do with who the children live with or how much child support is paid. That’s a separate process, and one the courts approach very differently.
The agreement must be in writing. Both people must sign it. And both must receive independent legal advice before signing. These aren’t optional extras. They’re the minimum legal requirements.
Expert Tip: Don’t confuse a postnuptial agreement with a general “we’ve agreed to be fair to each other” conversation. Without the correct form, the right advice and the right signatures, an informal arrangement is not enforceable as a financial agreement.
Can de facto couples sign a postnuptial agreement?
Yes. The financial agreement framework under the Family Law Act 1975 extends to de facto couples as well as married couples. If you’re in a de facto relationship, you can enter a financial agreement during the relationship or after it ends.
The requirements are the same: writing, signatures, and independent legal advice for each person.
It’s worth noting that de facto relationships in Australia carry significant legal rights and obligations, particularly where the relationship has lasted two years or more, or there is a child. If you’re in a long-term de facto relationship and haven’t formalised anything about property or finances, a financial agreement is worth considering.
Key Point: Whether you’re married or in a de facto relationship, the framework is the same. The Family Law Act 1975 governs both. There’s no separate Queensland law applying to family law financial agreements. The rules are national.
Why do couples make a financial agreement during marriage?
When someone walks into our office wanting a financial agreement mid-marriage, something has usually just changed. Not always a relationship crisis. Often it’s a shift in circumstances that made both people realise they hadn’t formally dealt with the financial side.
The most common triggers:
- One person receives an inheritance and wants to ensure it stays separate if the marriage ends.
- One spouse starts, buys or grows a business and wants to ring-fence business value from the personal pool.
- It’s a second marriage and both people have children from earlier relationships. They want to preserve assets for their respective children.
- There’s been a significant asset brought into the relationship that was never formally dealt with.
- The couple went through a difficult period, considered separating, and then reconciled. They want to document what they’ve agreed going forward.
- One person is about to receive a significant financial windfall, such as a redundancy payout, a settlement or a gift.
The couples who do this well come to it calmly, with time, and without one person pushing the other. The couples who struggle come to it in a hurry, with one side already calculating what they might lose.
Expert Tip: The backstory matters. If you’re considering a postnuptial agreement because something has just changed in your financial circumstances, that’s a sound reason to start the conversation. If you’re considering it because you’ve just had a serious argument and you’re not sure the marriage will last, the process requires a different kind of honesty about what you actually need.
What can a postnuptial agreement cover?
A financial agreement during marriage can cover:
- Real property, including the family home, investment properties and land.
- Business interests, including shares in private companies and partnership interests.
- Superannuation interests.
- Debts, including mortgages, loans and credit facilities.
- Financial resources such as trust interests or entitlements.
- Spousal maintenance, either agreeing to a set arrangement or ruling it out.
- Future assets, including property acquired or accumulated after the agreement is signed.
This is a broad scope. The detail matters. An agreement that deals with current assets but says nothing about future acquisition can leave significant gaps. A well-drafted agreement thinks ahead.
Key Point: Don’t assume a brief agreement is a safer agreement. Vague documents give rise to disputes. The specificity of the drafting is directly connected to whether the agreement does the job it was supposed to do.
A postnuptial agreement cannot decide where children will live or how much child support will be paid
This is the most common misconception we see.
People sometimes assume a financial agreement can resolve everything: the house, the kids, the money. It can’t. Parenting arrangements, including who children live with, how much time they spend with each parent, and how decisions get made, are dealt with separately. Child support is dealt with separately again, through Services Australia or a separate binding child support agreement.
Courts will not treat a financial agreement as settling parenting questions. And if children’s matters become contested, no financial agreement prevents a parent from applying to the Federal Circuit and Family Court of Australia for parenting orders.
Expert Tip: If you want to sort out everything at once, you’ll need more than one document. A financial agreement, a parenting plan or parenting orders, and potentially a child support agreement are three separate instruments. Your lawyer should tell you which combination suits your situation.
What makes a postnuptial agreement legally binding?
This is the question most people get wrong.
Many people assume that if both spouses sign the document, it’s binding. It isn’t. Signing is necessary, but it’s not sufficient.
For a financial agreement to be binding under the Family Law Act 1975, each of the following must be satisfied:
- The agreement must be in writing and signed by both parties.
- Before signing, each party must receive independent legal advice from a separate lawyer about the legal effect of the agreement and its advantages and disadvantages.
- Each lawyer must sign a statement confirming that advice was given.
- A copy of each lawyer’s statement must be provided to the other party or their lawyer.
That phrase, independent legal advice, is doing a lot of work. Each person needs their own lawyer. Not a shared lawyer. Not a lawyer who prepared the document and then explained it to both of you. Separate advisers, separate advice.
This is the thing people are most surprised to learn. They’ve talked it through, they agree on everything, and they assume one lawyer can just put it in writing. That’s not how it works. Using the same lawyer, or signing without proper advice, is one of the most common reasons these agreements are later challenged and set aside.
Expert Tip: Don’t sign a financial agreement at the end of a meeting where you also saw the lawyer who drafted it. See your own lawyer, separately, with enough time to ask questions and genuinely consider the advice. If you felt rushed, that matters.
Do both people need separate lawyers for a postnuptial agreement?
Yes. This is non-negotiable.
Each person must obtain independent legal advice from a separate qualified family lawyer. The lawyer advising one spouse cannot also advise the other, even if both people say they’re happy with the arrangement. Even if one person says they don’t want a lawyer. Even if the document seems simple.
If a party did not receive independent legal advice before signing, the agreement may be set aside later. Courts have done exactly that.
Key Point: The independent advice requirement protects both of you. It’s not bureaucratic box-ticking. It ensures that each person understood what they were agreeing to, what they were giving up, and whether the agreement was in their interests.
Can you be forced to sign a postnuptial agreement?
No. And if you were, the agreement is at serious risk of being set aside.
A financial agreement must be entered into freely. Courts can set aside a financial agreement where:
- It was obtained by fraud or non-disclosure of assets.
- A party entered it under duress or undue influence.
- The circumstances at the time of signing were unconscionable, meaning the situation was so unequal or unfair that it would be wrong to enforce the agreement.
- A material change in circumstances has occurred since the agreement was made, particularly involving children.
If your spouse has said something like “sign this tonight or you’ll get nothing, ” stop. Do not sign. Get your own lawyer first. A deadline imposed by the other party is not a legal requirement.
Expert Tip: The pressure to sign quickly is itself a warning sign. Genuine agreements are made with time on both sides. If you’re being rushed, say so to your own lawyer before you sign anything.
What happens if one spouse refuses to sign a postnuptial agreement?
Neither party can be compelled to enter a financial agreement. It requires both people to sign voluntarily.
If your spouse refuses to sign, the agreement cannot proceed in that form. That doesn’t necessarily mean the matter is unresolvable. It may mean the terms need further negotiation. It may mean a financial agreement isn’t the right approach. Or it may mean that if you’re already at the point of separation, consent orders or another process is more appropriate.
Refusing to sign is not itself a legal problem for the person refusing. It simply means there’s no agreement.
Key Point: A refusal to sign is useful information. It tells you where you both actually stand. If one person won’t engage with any process of formalising the financial relationship, that’s worth knowing before circumstances change significantly.
Can a postnuptial agreement be set aside later?
Yes. A court has the power to set aside a financial agreement in certain circumstances.
The most common grounds include fraud, material non-disclosure, duress, undue influence, unconscionable conduct, and a material change in circumstances affecting a child of the marriage.
This is why the requirements around independent advice, disclosure and genuine consent matter so much. An agreement that ticks those boxes is significantly harder to challenge than one that doesn’t. But no agreement is completely challenge-proof. Circumstances change, and courts retain a supervisory role.
Expert Tip: Treat the enforceability requirements not as obstacles, but as the thing that makes the agreement worth having. An agreement that was properly prepared, freely signed and fully disclosed is the one most likely to do its job if it’s ever tested.
Is a postnuptial agreement still useful if you are already separating?
It can be, but it may not be the right instrument.
Once you’re separated, a financial agreement made after the marriage ends is governed by a different provision of the Family Law Act 1975 than one made during the marriage. If you’ve already agreed on how to divide property, and you want to formalise that arrangement, consent orders approved by the Federal Circuit and Family Court of Australia may be a more appropriate path.
Consent orders are approved by a court, which gives them a different kind of enforceability. They can also deal with superannuation splitting in ways that sometimes require careful coordination. A financial agreement can still work after separation, but your lawyer should explain which instrument gives you the protection you’re actually looking for.
If you’re already separating, do not assume the answer is simply to sign a postnuptial agreement. Ask whether consent orders would give you a clearer and more suitable outcome.
Key Point: The right document depends on where you are in the relationship, not just what you want to achieve. One conversation with a family lawyer can clarify which path is appropriate before you invest time and cost in the wrong one.
What is the difference between a postnuptial agreement, consent orders and a separation agreement?
These three things serve different purposes and operate differently.
A postnuptial agreement is a private contract between two people about how property and finances will be treated if the relationship ends. It doesn’t require court approval. It’s binding if it meets the legal requirements.
Consent orders are orders made by the Federal Circuit and Family Court of Australia by consent. Both parties agree to the terms, and the court approves them. They carry the force of court orders. Consent orders are often used after separation to formalise property settlement.
A separation agreement is an informal term often used to describe any written document that records what two separated people have agreed. It is not a legal term of art, and an informal separation agreement is not automatically binding in the same way as a financial agreement or consent orders.
If you’ve agreed on terms, the question of which formal instrument to use is one your lawyer should answer based on your specific circumstances.
Expert Tip: The words “we’ve got it in writing” mean very different things depending on what was written, how it was prepared and what legal framework it operates under. An email agreeing to split the house does not have the same effect as consent orders.
How does a postnuptial agreement affect property settlement after separation?
If the agreement is binding, it replaces the court’s ability to make property settlement orders in the ordinary way. The parties have effectively contracted out of that part of the Family Law Act.
That’s a significant consequence. It means that if the agreement was made on terms that turned out to be very unequal, the court’s ability to correct that outcome is limited, unless grounds exist to set the agreement aside.
This is why the disclosure requirements and the independent advice requirement exist. They protect both parties from agreeing to something without understanding its long-term effect.
Key Point: A binding financial agreement limits what the court can do later. That’s exactly what it’s designed to do. Make sure the terms are ones you genuinely understand and accept before you sign, because walking back from a properly executed agreement is difficult.
What financial information must be disclosed before signing?
Both parties must make full and frank disclosure of their financial circumstances before entering a financial agreement.
This includes current assets, liabilities, income, superannuation interests and any financial resources such as trust interests or expected inheritances. Omitting or misrepresenting financial information is a basis on which a court may later set the agreement aside.
Disclosure is not a technicality. Courts treat non-disclosure seriously. If one party hides an asset and the other later discovers it, the entire agreement is at risk.
Expert Tip: Prepare a complete and accurate picture of your financial position before negotiations begin. Your lawyer should help you understand what needs to be disclosed. If you’re not sure whether something counts, disclose it.
How long does it take to prepare and sign a postnuptial agreement?
The realistic timeframe is four to twelve weeks in most cases, though it can be shorter where both parties are organised and in agreement on terms, and considerably longer where there is negotiation, complexity or delay.
The process involves:
- Both parties independently instructing their own lawyers.
- Disclosure of financial information on both sides.
- Drafting by one lawyer, review and negotiation.
- Each lawyer providing advice to their own client.
- Signing, with the correct certificates attached.
Rushing this process creates risk. An agreement signed under time pressure, without proper advice, is one of the most common reasons these documents are later challenged.
Key Point: There is no legally safe shortcut to the preparation process. If you need an agreement in place before a particular event, such as settlement on a property or a business transaction, start early.
How much does a postnuptial agreement cost on the Gold Coast?
The honest answer is that cost depends on complexity, the level of negotiation required and how much time both lawyers spend on the matter.
A straightforward agreement where both parties are in full agreement and the financial picture is simple will cost significantly less than one involving a business valuation, contested terms, multiple properties or superannuation splitting.
We don’t quote a fixed fee without understanding your circumstances. What we can tell you is that the cost of a properly prepared agreement is generally a fraction of the cost of contested property proceedings if the agreement is later needed and doesn’t exist.
For an accurate fee estimate for your situation, contact our team at C + K Family Lawyers on the Gold Coast. We’re happy to give you a clear picture of what’s involved before you commit to anything.
Expert Tip: Compare the cost of getting this right now against the cost of resolving a property dispute later without an agreement. The proportionality almost always favours getting independent advice early.
What if there is family violence or financial control?
If there is family violence, coercive control, financial abuse or significant power imbalance in the relationship, a financial agreement signed in that context is at serious risk of being set aside.
Courts are attentive to circumstances where one party was not in a position to negotiate freely, seek independent advice, or genuinely understand the document they signed.
If your partner is pressuring you to sign, controlling your access to financial information, threatening consequences if you refuse, or insisting you use their lawyer, those are circumstances your own lawyer needs to know about. Do not sign under those conditions.
If you need to speak with someone about safety before anything else, contact 1800RESPECT or your local police. Protecting your safety comes before protecting your financial position.
Expert Tip: If you’re in a situation involving family violence and your partner is insisting on a financial agreement, the first call you make should be to your own lawyer, from a safe location, without your partner present. The process should not begin until you have been able to speak freely and get genuine independent advice.
What should you do before agreeing to a postnuptial agreement?
Before you engage with the process or respond to any terms your partner has proposed, do these things:
Get your own lawyer first. Not a shared lawyer. Your own.
Gather a complete picture of your financial position: what you own, what you owe, your superannuation balance, any business interests, and any assets you’ve received as gifts or inheritance.
Take time. Don’t sign anything because a deadline has been imposed by your partner or because you feel that agreeing quickly will preserve the relationship.
Ask whether a financial agreement is the right instrument for your situation, or whether consent orders, a parenting plan or another document would be more appropriate.
And if there’s any pressure involved, name it to your lawyer before you do anything else.
Expert Tip: The conversation with your own lawyer should happen before any conversation with your partner about terms. Understanding your rights and your position first puts you in a genuinely informed place to negotiate.
Can C + K Family Lawyers help with a postnuptial agreement on the Gold Coast?
Yes. We prepare and advise on financial agreements for married and de facto couples at every stage of the relationship.
Whether you’re considering an agreement during a functioning marriage, dealing with changed financial circumstances, or working through what the right document is for your situation post-separation, our team can help you understand your options clearly.
We’re based at Westfield Coomera and advise clients across the Gold Coast.
If you’d like a confidential, no-obligation conversation about your circumstances, get in touch with the C + K Family Lawyers team. There’s no pressure to commit to anything in that first conversation.
Key Point: Getting advice early costs very little compared to resolving a dispute later without a clear agreement in place. The earlier you act, the more options you have.
Frequently asked questions about postnuptial agreements
Is a postnuptial agreement legally enforceable in Australia? It can be, if it meets the requirements of the Family Law Act 1975. Both parties must sign it, receive independent legal advice, and the agreement must include the required statements from each lawyer. Even a properly prepared agreement can be set aside in certain circumstances, such as non-disclosure or duress, so the process of preparing it matters as much as the document itself.
Can we use one lawyer to prepare and sign a postnuptial agreement? No. Each person must receive independent legal advice from a separate qualified family lawyer. Using a single shared lawyer, or signing without independent advice, is one of the most common reasons financial agreements are later challenged and set aside.
What’s the difference between a postnuptial agreement and consent orders? A postnuptial agreement is a private contract that doesn’t require court approval. Consent orders are approved by the Federal Circuit and Family Court of Australia and carry the force of court orders. For couples who have already separated, consent orders are often the more appropriate path. Your lawyer should advise which instrument suits your situation.
Can a postnuptial agreement decide where children will live? No. A financial agreement deals with property, financial resources, superannuation and spousal maintenance. Parenting arrangements, including who children live with and spend time with, are dealt with separately through parenting plans or parenting orders. Child support is also a separate matter.
Do we need a postnuptial agreement or a separation agreement? “Separation agreement” is an informal term that doesn’t carry the legal weight of a binding financial agreement or consent orders. If you want an arrangement that is genuinely enforceable, you need either a financial agreement that meets the Family Law Act 1975 requirements or consent orders approved by the court. Get advice on which is appropriate for your stage and circumstances.
What to do next
If you’re already married and considering a financial agreement, the most useful thing you can do today is speak with your own family lawyer before agreeing to anything with your partner.
Knowing your position first is not adversarial. It’s sensible. The couples who manage this process well are almost always the ones who got proper advice early, understood what they were agreeing to, and had time to think.
The ones who struggle are usually the ones who signed quickly, under pressure, with incomplete information.
You don’t have to be in that second group.
If you’d like to talk through your situation with the C + K Family Lawyers team on the Gold Coast, reach out for a confidential, no-obligation conversation. We’ll tell you where you stand, what your options are, and what a sensible next step looks like.
This article is general information only and is not legal advice. Family law outcomes depend on your individual circumstances. For advice about your situation, speak with a qualified family lawyer.
About the Author
Christopher (Chris) Jones is the Principal Lawyer and co-founder of CK Family Lawyers, a Queensland family law firm. Chris advises on divorce, property settlement, parenting arrangements, binding financial agreements, mediation and domestic violence matters. After working in legal environments where clients felt depersonalised and lost in jargon, he co-founded the firm with Krystina Jones on the belief that people deserve family lawyers who genuinely care, and he works directly with his clients throughout their matters.
