A prenup can be thrown out in New Brunswick. Under section 43 of the Marital Property Act (RSNB 2012, c 107), a court may disregard any provision of a marriage contract if a spouse signed without independent legal advice and enforcing the term would be inequitable. Courts also set aside agreements for non-disclosure, duress, or unconscionability.
In New Brunswick, what most people call a "prenup" is legally a marriage contract, one type of domestic contract governed by the Marital Property Act and federal Divorce Act principles. While New Brunswick courts generally enforce valid agreements, the law gives judges express statutory power to override prenup terms in defined circumstances. This guide explains exactly when and how a prenup can be thrown out in New Brunswick, the statutory and case-law grounds, the costs involved, and what you can do to protect or challenge an agreement.
Key Facts: Prenup Challenges in New Brunswick
| Factor | Detail |
|---|---|
| Filing Fee (divorce) | $110 total ($100 petition + $10 clearance certificate) |
| Waiting Period | 31-day appeal period after divorce judgment before it takes effect |
| Residency Requirement | One spouse ordinarily resident in NB for 1 year before filing |
| Grounds (divorce) | Breakdown of marriage: 1-year separation, adultery, or cruelty |
| Property Division Type | Equal (50/50) division of marital property by default |
| Governing Statute | Marital Property Act § 43 |
Filing fees as of June 2026. Verify with your local clerk at the Court of King's Bench, Family Division.
Can a Prenup Be Thrown Out in New Brunswick?
Yes, a prenup can be thrown out in New Brunswick. Under Marital Property Act § 43 (RSNB 2012, c 107), a court may disregard any provision of a domestic contract if a spouse entered it without independent legal advice and applying the term would be inequitable. Courts also void agreements obtained through fraud, duress, or non-disclosure.
New Brunswick treats marriage contracts as a hybrid of contract law and family-law statute. A prenup that fails ordinary contract requirements, such as one signed under duress or based on concealed assets, can be struck under general contract principles. Separately, the Marital Property Act adds a family-law override: even a technically valid contract can be set aside where enforcing it would be inequitable and the challenging spouse never received independent legal advice. The Supreme Court of Canada in Hartshorne v. Hartshorne, 2004 SCC 22, confirmed that provincial property-agreement legislation governs this analysis, and that courts respect freely negotiated bargains while retaining discretion to intervene where the result is unfair. A challenge does not guarantee the whole contract collapses; a court may sever and disregard only the offending provision while enforcing the rest.
Statutory Grounds: Marital Property Act Section 43
The primary statutory ground for throwing out a prenup in New Brunswick is Marital Property Act § 43. This section allows a court to disregard any provision of a domestic contract if the agreement was made without independent legal advice and enforcing it would be inequitable in all the circumstances. Both conditions must be met for the override to apply.
Section 43 (originally numbered section 41 under SNB 1980, c M-1.1, before the 2012 consolidation) sets out two triggering conditions. The first applies to contracts made before January 1, 1981, that did not contemplate the Act coming into force. The second, and far more common ground, applies where the spouse challenging a provision "entered into the domestic contract without receiving legal advice from a person independent of any legal advisor of the other spouse." In either case, the court must also conclude that applying the provision would be inequitable in all the circumstances of the case. This two-part structure means lack of independent legal advice alone is not enough; an unconscionable prenup challenge under section 43 also requires proof that enforcement would produce an unfair result. This is why both spouses should retain separate lawyers before signing any marriage contract in New Brunswick.
Limits on What a Prenup Can Cover
A prenup in New Brunswick cannot validly determine parenting arrangements or waive child support. Under Marital Property Act § 34, a marriage contract cannot deal with the right to decision-making responsibility or parenting time for children. Any clause attempting to limit child support is unenforceable because support is the child's right.
Section 34(d) of the Marital Property Act bars marriage contracts from governing the custody of or access to children, language that maps onto the modern terms parenting arrangements and parenting time used in the 2021 amendments to the Divorce Act, R.S.C. 1985, c. 3. New Brunswick courts decide all child-related matters under the best-interests-of-the-child standard at the time of separation, not based on a document signed years earlier. The same principle applies to child support: a judge can ignore any clause concerning child support, because support belongs to the child and is calculated under the Federal Child Support Guidelines. A prenup that purports to fix or eliminate these obligations is automatically vulnerable. By contrast, provisions dividing property, allocating debt, and addressing spousal support are permitted, though spousal support waivers face heightened scrutiny if they later produce hardship.
How Non-Disclosure Voids a Prenup
Failure to disclose assets is one of the most common reasons a prenup is thrown out in New Brunswick. While the Marital Property Act does not list disclosure as a formal requirement, the Supreme Court of Canada held in Rick v. Brandsema, 2009 SCC 10, that deliberately concealing financial details can render an agreement unenforceable for producing an unfair result.
In Rick v. Brandsema, the husband hid the true value of the couple's assets, and the Court set the agreement aside because the resulting bargain was substantially unfair and built on misinformation. The reasoning applies directly to challenging a prenup in New Brunswick: full and frank disclosure of income, property, and debts is essential to an enforceable marriage contract. When one spouse signs without knowing the other's real financial position, the bargain is not truly informed, and courts treat the non-disclosure as a powerful factor in finding the agreement inequitable under section 43 or unconscionable under general contract law. Each party should exchange a sworn statement of net worth, attach it as a schedule to the contract, and keep copies. A prenup that omits or misstates major assets, a hidden business interest, a pension, or out-of-province property, gives the other spouse strong grounds to have the agreement set aside.
Duress, Undue Influence, and Timing
A prenup can be thrown out in New Brunswick if it was signed under duress or undue influence. Courts scrutinize agreements presented shortly before the wedding, where one spouse had no realistic chance to obtain independent legal advice or negotiate. Pressure to sign "or the wedding is off" days before the ceremony is a recognized red flag for an invalid prenup.
Duress in this context means improper pressure that overrides a spouse's free will. Canadian courts have repeatedly struck or limited agreements signed days before a wedding when the timing left no room for genuine negotiation or reflection. The closer the signing is to the ceremony, and the greater the imbalance in bargaining power, the more likely a New Brunswick court is to find the contract was not entered freely. The remedy turns on the facts: a court may disregard the entire agreement or only specific provisions. To reduce this risk, couples should finalize a marriage contract well in advance of the wedding, ideally a month or more, document that both parties had time to review drafts, and ensure each spouse independently retained their own lawyer. A contract signed calmly, with advice and time, is far harder to challenge for duress than one signed under deadline pressure.
Unconscionability and Spousal Support Waivers
A spousal support waiver in a New Brunswick prenup can be overridden even if the rest of the contract is valid. Under the Supreme Court of Canada's two-stage test in Miglin v. Miglin, 2003 SCC 24, a court asks whether the agreement was fairly negotiated and whether it still reflects the parties' intentions and complies with the Divorce Act at the time of separation.
The Miglin test first examines the circumstances of formation: full disclosure, independent legal advice, and the absence of pressure. It then examines whether enforcing the waiver at the time of the support application would substantially depart from the objectives of the Divorce Act, R.S.C. 1985, c. 3. A waiver that was reasonable when signed can become unconscionable if circumstances change dramatically, for example, if one spouse left the workforce to raise children and would face financial desperation while the other holds significant wealth. When a court declines to enforce a support waiver, it does not leave the spouse unsupported; the Spousal Support Advisory Guidelines provide ranges for amount and duration. This is why an unconscionable prenup challenge often targets the support clause specifically rather than the entire agreement. Property-division terms may survive while a one-sided support waiver is struck.
Costs of Challenging a Prenup in New Brunswick
Challenging a prenup in New Brunswick is significantly more expensive than the $110 divorce filing fee, because it usually requires contested litigation. Legal fees for a disputed prenup challenge commonly range from $5,000 to $30,000 or more, depending on the complexity of assets, the need for valuations, and whether the matter proceeds to trial.
The baseline court cost is modest. The divorce filing fee is $110 ($100 for the petition plus $10 for the Central Registry of Divorce Proceedings clearance certificate) under Rule 72.24 of the Rules of Court, and a post-divorce Certificate of Divorce costs $7. New Brunswick residents on social assistance under the Family Income Security Act or represented by Legal Aid are exempt from filing fees under Rule 72.24(2). The real expense lies in the legal work to set aside an invalid prenup: gathering evidence of non-disclosure, retaining financial experts to value businesses or pensions, conducting examinations, and litigating before the Court of King's Bench, Family Division. Filing fees as of June 2026. Verify with your local clerk. Because a challenge is fact-intensive and uncertain in outcome, many spouses negotiate a settlement rather than risk a full trial, particularly where the agreement has both strong and weak provisions.
| Cost Item | Typical Amount (June 2026) |
|---|---|
| Divorce filing fee | $110 total |
| Certificate of Divorce | $7 |
| Filing fee waiver (social assistance / Legal Aid) | $0 |
| Lawyer for prenup drafting (each spouse) | $1,500 – $4,000 |
| Contested prenup challenge (legal fees) | $5,000 – $30,000+ |
| Asset valuation / financial expert | $1,500 – $7,500+ |
Figures are estimates for general planning. Verify current court fees with the Court of King's Bench, Family Division.
How to Protect a Prenup From Being Thrown Out
To keep a prenup enforceable in New Brunswick, both spouses should obtain independent legal advice, exchange full financial disclosure, and sign well before the wedding without pressure. These three steps directly answer the grounds for challenge under Marital Property Act § 43 and the Supreme Court of Canada's fairness tests.
A well-drafted marriage contract anticipates every common attack. First, each spouse retains a separate lawyer, because section 43 lets a court disregard provisions where the challenging spouse lacked independent legal advice. Second, both parties attach sworn statements of net worth listing all property, income, pensions, and debts, neutralizing a non-disclosure argument under Rick v. Brandsema. Third, the contract is negotiated and signed with enough lead time before the wedding to defeat any duress claim. Fourth, the document is in writing, signed, and witnessed, satisfying the formal requirements for a valid domestic contract. Finally, parties should avoid grossly one-sided terms, since unconscionable provisions, especially spousal support waivers, invite scrutiny under Miglin. Following these steps does not make a prenup bulletproof, courts retain discretion, but it dramatically reduces the odds that a New Brunswick court will throw it out.