Published on January 21, 2025
Marriage and relationships are about love, trust and shared goals. Marriage is also about life’s practical realities – like managing finances and protecting your assets.
For many couples, these conversations don’t stop after the wedding. Whether it’s due to a significant change in financial circumstances or wanting to create a clear plan for the future, a postnuptial agreement can be a practical and proactive solution.
In Australia, postnuptial agreements – also known as binding financial agreements – allow married couples or those in de facto relationships to outline how their assets and financial resources will be divided if the relationship ends. These agreements can also cover spousal maintenance and protect interests in a family business or blended family arrangements.
At Unified Lawyers we know navigating these legal agreements can be daunting. That’s why we’ve put together this guide to help you understand postnuptial agreements and how they can bring clarity, security and peace of mind to your financial future.
How Do Postnuptial Agreements Work?
A postnuptial agreement is more than just a piece of paper; it’s a carefully drafted legal document that provides clarity and security for couples. These agreements can cover everything from how assets will be split to spousal maintenance.
In Australia post nuptial agreements fall under the Family Law Act. To be legally binding certain requirements must be met. Both parties must fully and fairly disclose their financial circumstances, and independent legal advice must be obtained by each person before signing the agreement. This ensures both parties understand their rights and the implications of the terms.
The High Court case of Thorne v Kennedy shows the importance of fairness and transparency in creating binding financial agreements. Agreements that don’t meet these standards can be challenged or be unenforceable.
When done properly a postnuptial agreement can be a powerful tool to protect assets, avoid future disputes and give peace of mind for both parties.
Why Consider a Postnuptial Agreement
Couples create postnuptial agreements for various reasons, often tied to significant changes or milestones in their relationship or financial lives. Here are some of the most common situations where an agreement can be useful:
- Protecting significant assets: If one or both partners have acquired substantial wealth, property or business interests during the relationship, a postnuptial agreement ensures those assets are accounted for.
- Blended families: Postnuptial agreements can help couples with blended families outline how assets will be divided to protect the financial interests of children from previous relationships.
- Financial changes: Life doesn’t stay the same and major changes such as receiving an inheritance, selling a business or facing unexpected financial challenges can trigger the need for a legal agreement.
- Family businesses: For couples involved in a family business a postnuptial agreement can prevent disputes and clarify ownership and operational rights.
- Future clarity: These agreements reduce uncertainty, avoid future disputes and give couples peace of mind about how financial matters will be managed in the event of separation.
While it may seem scary to talk about finances, setting out clear terms can actually strengthen a relationship by building trust and transparency.

Pros and Cons of a Postnuptial Agreement
Like any legal agreement a postnuptial agreement has its advantages and disadvantages. Knowing both will help you decide if this type of agreement is for you.
Advantages of a Postnuptial Agreement
- Setting out how assets and financial resources will be managed reduces uncertainty and conflict providing financial clarity and security.
- Whether it’s property, investments or a family business a postnuptial agreement can help to protect significant assets.
- Postnuptial agreements can be flexible, addressing changes in financial circumstances that weren’t anticipated when the relationship started and allows.
- By agreeing to terms upfront couples can avoid long and costly legal battles in the event of a separation.
Disadvantages of a Postnuptial Agreement
- Talking about finances and planning for the worst-case scenario are difficult conversations and can be tough for some couples.
- If the agreement isn’t properly prepared—such as lack of full financial disclosure or independent legal advice—it may be unenforceable.
- A legally sound postnuptial agreement requires the involvement of experienced family lawyers which means an upfront expense.
While the benefits far outweigh the drawbacks it’s important to work with lawyers who can guide you through the process and ensure the agreement meets all legal requirements and your individual circumstances.
What’s in a Postnuptial Agreement?
A postnuptial agreement can cover a range of financial and practical matters specific to each couple. Some things that may be covered include:
- How marital property and separate property will be divided in the event of separation.
- What financial support will be provided if one partner needs it after the relationship ends.
- Who will be responsible for existing debts such as loans or credit cards.
- Protecting ownership in a family business or other ventures to avoid future disputes.
- Future financial arrangements such as life insurance policies, superannuation or future income from investments.
- Accounting for children from previous relationships especially in blended families to ensure their financial interests are protected.
But please note postnuptial agreements can’t cover child custody or child support as these are dealt with separately under Australian family law.

Requirements for Postnuptial Agreements in Australia
For a postnuptial agreement to be enforceable in Australia it must meet the requirements of the Family Law Act. These safeguards are to ensure fairness and prevent disputes over the agreement’s validity.
The requirements are:
- Full financial disclosure: Both parties must provide a full and frank account of their financial circumstances including assets, liabilities and income.
- Independent legal advice: Each party must obtain advice from separate lawyers to ensure they understand the terms and implications of the agreement. A signed statement from each lawyer is also required.
- Voluntary agreement: The agreement must be entered into willingly, without pressure, duress, or unconscionable conduct.
- Compliance with legal formalities: The document must be in writing, signed by both parties and meet all the procedural requirements under the Family Law Act.
By meeting these requirements, you not only strengthen the agreement but also have peace of mind for both parties.
Can a Postnuptial Agreement be Challenged?
While a postnuptial agreement can give you clarity and security it’s not immune to legal challenges. One party may argue the agreement is invalid or shouldn’t be enforced. Here are some grounds to challenge a postnuptial agreement:
- Lack of full financial disclosure: If one party didn’t disclose all their financial resources, assets or liabilities the agreement may be unfair.
- Failure to obtain independent legal advice: Both parties must have received advice from separate lawyers before signing the agreement. Without this the agreement may be invalid.
- Duress or undue influence: An agreement must be voluntary. If one party was pressured, coerced or felt forced to sign it can be challenged in court.
- Unconscionable conduct: If the terms of the agreement are grossly unfair or exploitative they may not be enforceable.
The High Court case of Thorne v Kennedy is a warning. In this case the court declared a binding financial agreement invalid because it was signed under duress and had unfair terms. This landmark decision shows the importance of fairness, transparency and compliance with legal requirements when creating these agreements.
If you’re considering a postnuptial agreement work with experienced family lawyers to avoid the pitfalls and get a robust, fair and enforceable agreement.
Postnuptial Agreements vs Prenuptial Agreements
While postnuptial and prenuptial agreements serve the same purpose, the key difference is timing. A prenuptial agreement is made before marriage or entering into a de facto relationship and is likely to address the protection of assets brought into the relationship while a postnuptial agreement is made after the relationship has already started and may address the changes that have occurred in the relationship, such as starting a business or receiving an inheritance.
Both types of agreements are binding under the Family Law Act if they meet the necessary requirements such as full financial disclosure and independent legal advice. Whether made before or during the relationship these agreements aim to reduce disputes and protect the financial interests of both parties.
Which one is best for you depends on the timing and purpose of the arrangement. Talk to experienced lawyers to make sure the agreement is right for you and compliant with Australian family law.
How to Start the Conversation About a Postnuptial Agreement
Talking about a postnuptial agreement can be awkward but it doesn’t have to be a difficult conversation. Here are some tips to approach the topic with sensitivity and clarity:
- Choose the right time: Don’t bring it up during a stressful moment or when emotions are running high. Instead pick a time when you and your partner can have a calm and uninterrupted conversation.
- Frame it as a joint decision: Say the agreement is about both parties and fairness not mistrust or preparing for the worst.
- Focus on the benefits: Explain how the postnuptial agreement will bring clarity, protect shared goals like a family business or protect significant assets for both of you.
- Be honest about your intentions: Transparency is key. Explain why you think the agreement is important for your financial future and your relationship.
- Get legal advice early: Suggest you both see family lawyers together to get a better understanding of the legal aspects and to make the process professional.
Talking about it with respect and open communication can turn what might be a hard topic into a positive and empowering conversation for both.
Can You Do a Postnuptial Agreement Without a Lawyer?
Technically you can draft a postnuptial agreement without a lawyer, but it’s not recommended as there are strict legal requirements that include receiving independent legal advice. Without this advice the agreement is unlikely to be enforceable.
On top of this, a lawyer can help to draft a well written agreement that is fair and unambiguous and is compliant with Australian Family Law.
Trying to do a postnuptial agreement without professional help may save you money upfront but can lead to costly disputes or invalid agreements down the track. Engaging experienced family lawyers gives you peace of mind and ensures the agreement is tailored to your situation
Postnuptial Agreement FAQs
How much does a postnuptial agreement cost in Australia?
The cost of a postnuptial agreement varies depending on your financial situation and the time it takes to negotiate and finalise the terms. There’s an upfront cost but investing in legal advice will ensure the agreement is robust and enforceable and can save you from costly disputes down the track.
Can a postnuptial agreement include child custody or support?
No. Child custody and child support are dealt with separately under Australian family law and can’t be included in a postnuptial agreement.
Are postnuptial agreements legally binding in Australia?
Yes, if they meet the requirements of the Family Law Act. This includes full financial disclosure, independent legal advice for both parties and compliance with procedural formalities.
What if one party doesn’t comply with the agreement?
If one party breaches the agreement the other party can seek enforcement through the court. The enforceability of the agreement will depend on whether it meets the legal requirements and is considered fair by the court.
Can a postnuptial agreement be updated?
Yes, agreements can be varied to reflect changes in your financial situation such as acquiring new assets or starting a business. You should consult lawyers when making any variations to ensure the revised agreement is enforceable.

How We Can Help
At Unified Lawyers we know working your way through the legal side of a postnuptial agreement can be daunting. That’s why we’re here to make the process as easy as possible.
Our team of experienced family lawyers will guide you through every step from explaining your rights and obligations to drafting a legally binding agreement tailored to your situation. We will ensure you get clear and practical advice; all legal requirements are met including full financial disclosure and independent legal advice and your agreement is fair, enforceable and protects your interests.
Whatever your reason for having a postnuptial agreement we’ll help you get clarity and security. Get in touch today.
Published on January 21, 2025
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