A prenup, formally called a binding financial agreement (BFA), can be a powerful tool for protecting your assets before or during a relationship. But what happens if that agreement is challenged, set aside, or simply never enforced? The short answer is that Australian family law takes over, and the court applies its own framework for dividing property. Understanding this scenario can help you appreciate why getting a prenup right from the outset is so important.
When does a prenup fail to hold up?
Not every binding financial agreement survives legal scrutiny. Under the Family Law Act 1975, a court can set aside a BFA on a number of grounds, including:
- Fraud, such as one party concealing assets or providing false information
- Duress, undue influence, or unconscionable conduct at the time of signing
- One or both parties not receiving independent legal advice before signing
- A material change in circumstances that makes enforcing the agreement unjust, particularly where a party would be left without adequate means of support
- The agreement being impractical to carry out
- Formal defects, such as missing signatures or certificates of independent legal advice
Any one of these issues can be enough for a court to declare the agreement void. Once that happens, the parties lose the certainty the agreement was meant to provide. Understanding what makes a binding financial agreement enforceable from the beginning is the best way to prevent this outcome.
What the court does instead
If a prenup is set aside or was never validly executed in the first place, the Family Court (or Federal Circuit and Family Court of Australia) steps in to determine how property and financial resources are divided. This process follows a well-established four-step approach.
First, the court identifies and values all assets, liabilities, and financial resources held by both parties, whether acquired before or during the relationship. Second, it assesses the contributions each party made, including financial contributions, non-financial contributions, and contributions as homemaker or parent. Third, the court considers future needs factors, such as the age and health of each party, earning capacity, care of children, and standard of living. Finally, it determines what division is just and equitable in all the circumstances. That last step is deliberately broad, and outcomes can vary considerably from case to case.
Why the outcome could be very different from what you expected
One of the main reasons people enter into a prenup is to avoid the uncertainty of a court-determined outcome. Without a valid agreement, there is no guarantee that assets you brought into the relationship will remain yours, that a family business will be protected, or that an inheritance will be quarantined. Courts have wide discretion, and even a short relationship can give rise to a significant financial claim depending on the contributions and needs involved.
This is especially relevant for people who own a business, hold significant pre-relationship assets, or have children from a prior relationship. If you are in any of these situations, it is worth reading about whether a prenup can protect a business in Australia before assuming that your assets are safe.
Can you draft a new agreement after the original fails?
Yes, in many cases you can. If a prenup is set aside before separation, or if both parties agree to terminate it during the relationship, a new binding financial agreement can be drafted to replace it. If the relationship has already broken down, a financial agreement can still be made post-separation as a way of documenting a negotiated settlement and avoiding court proceedings. However, all the same formal requirements apply: both parties must receive independent legal advice, the agreement must be signed voluntarily, and full and frank financial disclosure is essential.
It is also possible to apply to the court for consent orders, which formalise an agreed property division and provide a level of finality that a BFA can sometimes lack.
The financial and emotional cost of enforcement failure
When a prenup falls apart, the costs are rarely just financial. Litigation is expensive, often running into tens of thousands of dollars in legal fees. It is also time-consuming. Property disputes in Australia can take years to resolve, particularly when significant assets, competing valuations, or contested contributions are involved. The stress of prolonged legal proceedings at an already difficult personal time should not be underestimated.
There is also the issue of interim arrangements. While a dispute is being resolved, there can be uncertainty about who has access to what, who services shared debts, and how joint assets are managed. These practical disruptions can affect businesses, housing, and day-to-day finances in ways that are difficult to reverse.
How to reduce the risk of your prenup not holding up
The most reliable way to protect yourself is to have the agreement drafted and executed correctly in the first place. This means working with a qualified family lawyer who specialises in BFAs, ensuring both parties receive genuinely independent legal advice (from separate lawyers), providing full financial disclosure, and avoiding any pressure or urgency around the time of signing. Reviewing the agreement periodically and updating it after major life events, such as having children or a significant change in assets, also reduces the risk of a future challenge.
A prenup is not a set-and-forget document. Treating it as one is exactly how couples end up in court arguing about an agreement they thought was settled years earlier.
Getting the right advice before it is too late
If you are concerned about the validity of an existing agreement, or if you are considering a prenup for the first time, specialist legal advice is essential. The stakes are high and the technical requirements are strict. A well-drafted binding financial agreement, properly signed and executed, gives you genuine protection. An improperly prepared one may offer very little at all.
Rockwell Family Law Services works with clients across Australia on binding financial agreements, from initial drafting through to enforceability reviews. Contact us today to speak with a family lawyer who understands both the technical and personal dimensions of this process.