Pay now, argue later: Supreme Court refuses to suspend enforcement of SOPA adjudication judgments
When an adjudication goes against you under the Building and Construction Industry (Security of Payment) Act 2021 (WA) (SOPA), can you put enforcement on hold while you pursue your larger claim against the contractor? In Aaro Group Pty Ltd v Monadelphous Engineering Associates Pty Ltd [2026] WASC 143, the answer was no.
Principal Registrar Griffin of the Supreme Court of Western Australia refused Monadelphous’s application to suspend two judgments based on adjudication determinations totalling about $3.29 million (ex GST). Most of Monadelphous’s evidence was ruled inadmissible, including material from the adjudications themselves, because s 55(4) of SOPA prevents evidence of what was said or done in an adjudication being used in court without both parties’ consent.
Key takeaways
Adjudication material stays in the adjudication. Under s 55(4) of SOPA, evidence of anything said or done in an adjudication is generally inadmissible in court unless both parties consent. That includes expert reports and submissions lodged in the adjudication.
A suspension application is not a second go at the merits. Where a party uses a suspension application to argue that the adjudicator got it wrong, s 55(4) will ordinarily exclude the adjudication material it relies on.
The test is the contractor’s ability to repay the adjudicated sum. A suspension will generally only be ordered where the principal will almost certainly suffer irreparable prejudice because the contractor won’t be able to repay the adjudicated amount if later ordered to. A large competing damages claim is not enough.
Evidence must be admissible. Hearsay without a stated source, and opinion evidence, will be excluded.
Who needs to know?
Principals and head contractors facing enforcement of an adjudication determination, or considering a suspension application.
Contractors and subcontractors enforcing determinations as judgments.
In-house legal teams and advisers preparing evidence in SOPA enforcement proceedings.
Background
Two determinations, two judgments
Aaro Group (Aaro) obtained two adjudication determinations against Monadelphous Engineering Associates (Monadelphous):
a determination of 21 August 2025 for $2,580,558.63 (ex GST), which Aaro filed in the Supreme Court on 26 September 2025
a determination of 20 November 2025 for $709,601.88 (ex GST), which Aaro filed on 9 December 2025.
Under s 54 of SOPA, a certified copy of a determination filed in court is taken to be a judgment of that court and can be enforced like any other judgment.
Enforcement action
On 20 November 2025, a debt appropriation order was made against Monadelphous’s account with National Australia Bank, and NAB paid $2 million to Aaro. On 9 December 2025, Aaro applied for a second debt appropriation order directed to Westpac.
On the same day, Monadelphous commenced separate Supreme Court proceedings against Aaro, claiming damages for breach of contract (which it estimated at around $18 million) and restitution under s 55(3) of SOPA of amounts paid under the determinations.
The suspension application
Monadelphous then applied under s 15 of the Civil Judgments Enforcement Act 2004 (WA) to suspend both judgments, set aside the NAB order and have the Westpac application refused. It said there were special circumstances, because:
Aaro had fundamentally failed to perform the work, or to perform it properly
an internal administrative error meant Monadelphous could not properly respond to the claim in the first adjudication
its breach of contract claim far exceeded the judgment debts
there was a genuine risk Aaro could not pay if Monadelphous won that claim.
The decision
Adjudication evidence was inadmissible
Monadelphous relied on a 778-page affidavit, together with exhibits that included expert reports it had lodged in the adjudications and a later adjudication determination. Aaro objected to much of that material and did not consent to the use of adjudication evidence.
Section 55(4) of SOPA provides that evidence of anything lawfully said or done in the course of an adjudication is not admissible before a court unless the parties consent.
The Registrar considered two earlier WA decisions:
In Cape Range Electrical Contractors Pty Ltd v Austral Construction Pty Ltd [2012] WASC 304, decided under the former Construction Contracts Act, Pritchard J held that the similar prohibition was directed at proceedings dealing with the merits of the contractual dispute. It did not prevent adjudication material being used in proceedings challenging the validity of a determination.
In Grounded Construction Group Pty Ltd v KW Civil & Construction Pty Ltd [2025] WASC 307, Lundberg J held that adjudication material going to the merits will ordinarily be caught by s 55(4) in an application to set aside a statutory demand.
Monadelphous argued that the suspension application was part of the same proceedings and that s 55(4) should not limit the Court’s control over its own judgments. The Registrar disagreed. The application did not challenge the validity of the adjudications. Instead, Monadelphous was seeking to engage with the merits of the dispute, which made it more like Grounded Construction than Cape Range.
The Registrar tied this to SOPA’s purpose. The Act provides a fast mechanism to keep cash flowing to contractors. If there is a substantive contractual dispute, the parties are free to pursue it separately. It is consistent with that approach that evidence from the adjudication is inadmissible outside that process.
Hearsay and opinion evidence also excluded
Much of the remaining evidence also failed:
A general statement in the affidavit that facts were based on the deponent’s knowledge or “the sources referred to” did not cure hearsay. For example, the assertion that an “internal administrative oversight” caused Monadelphous’s failure in the first adjudication did not identify its source, and was excluded.
Statements of opinion, including a witness’s views about Aaro’s financial position, were excluded.
The Registrar concluded that most of Monadelphous’s evidence was inadmissible.
No special circumstances
The party seeking a suspension must establish special circumstances. A stay of a judgment based on an adjudication will generally be appropriate where it is certain, or almost certain, that the principal will suffer irreparable prejudice because the contractor will be unable to repay the adjudicated sum if ordered to do so.
Monadelphous’s first two grounds depended largely on the excluded adjudication material. Its remaining grounds focused on whether Aaro could pay a damages award of around $18 million in the separate proceedings. That was the wrong question. The issue was whether Aaro could repay the much smaller adjudicated sums, and the evidence did not address that.
The application was dismissed with costs. The judgments were not suspended, the NAB order stood, and there was no basis to refuse the Westpac application.
What this means in practice
For principals and head contractors
Make your case in the adjudication. Once a determination is made, you generally can’t reargue it on a suspension application. Your remedy for a substantive dispute is separate proceedings, and in the meantime you will usually have to pay.
Focus on repayment risk. A suspension application should be directed to clear, admissible evidence that the contractor will be unable to repay the adjudicated amount, not to the strength of your wider claims.
Prepare fresh, admissible evidence. Don’t rely on material lodged in the adjudication unless the other party consents. Identify the source of any information and belief, and avoid opinion evidence unless it comes from a properly qualified expert.
For contractors and subcontractors
Enforcement is robust. Determinations filed as judgments can be enforced promptly, including through debt appropriation orders against the principal’s bank accounts.
Consider objecting to adjudication material. If a principal relies on material from the adjudication in court, consider whether to object under s 55(4), as Aaro did successfully here.
How we can help
Lang Litigation and Construction Law acts for principals, contractors and subcontractors in adjudications and in enforcing and resisting adjudication determinations under the Building and Construction Industry (Security of Payment) Act 2021 (WA). If you need advice on enforcing a determination, or on your options after an adverse determination, contact us.
This article is general information only and is not legal advice. You should seek specific advice about your circumstances.