Contractor Dispute in WA Magistrates Court — Defendant's Guide

A contractor has filed a Minor Case Claim against you in the WA Magistrates Court — typically for an unpaid invoice — and you are wondering how to respond. Or you are a tradesperson who has been counter-sued by a homeowner claiming defective work. Either way, contractor disputes make up a significant share of minor case filings, and the procedural path depends on whether the dispute crosses into regulated building work territory.

Is It a Magistrates Court Matter?

Not all contractor disputes belong in the Magistrates Court. Western Australia has a strict jurisdictional carve-out for regulated building work under the Building Services (Complaint Resolution and Administration) Act 2011. If the dispute involves:

• Defective residential building work performed by a registered builder
• A home building contract breach
• A remedy order under the Building Services Act

Then the matter falls under the Building Commissioner or the State Administrative Tribunal (SAT), not the Magistrates Court. The court cannot hear building disputes within the Building Commission's statutory domain.

If the dispute is about an ordinary trade services contract — a plumber's invoice, a landscaper's bill, an electrician's charges for non-building work — and the amount is under $10,000, it proceeds as a standard minor case.

Responding to the Claim

You have 14 days from service (21 days if served interstate) to lodge Form 15A on the eCourts Portal. Your options:

Defend the full claim. Complete Part F (deny) and Part H (your defence). If a contractor is suing for $7,000 in unpaid work, and you believe the work was incomplete or defective, your Part H should set out exactly what was not done, what was done poorly, and any quotes you obtained for remedial work.

Counterclaim. If the contractor's defective work cost you money to fix, you can file a counterclaim through Part I of Form 15A for your repair costs. If your counterclaim exceeds $10,000, the matter may move to General Procedure.

Partial admission. You agree the contractor did some work worth payment, but not the full invoiced amount. Offer the admitted portion in Part F and defend the balance in Part H.

Evidence That Matters

Contractor disputes are won or lost on documentation:

• The original contract or written quote (even a text message agreeing to a price counts)
• Photos of the work — before, during, and after
• Independent quotes for remedial or completion work
• Payment records showing what you have already paid
• Any written complaints you sent to the contractor during the job

Organise everything chronologically, name files clearly, and bring both a digital copy (for the eCourts Portal) and a printed bundle to the hearing.

The Hearing

At the status conference, the magistrate will explore whether a settlement is possible. Many contractor disputes settle at this stage — the parties agree on a reduced payment or a scope of remedial work. If no agreement is reached, the matter proceeds to a hearing where both sides present their evidence and the magistrate makes a binding decision.

Lawyers generally cannot represent parties in minor case hearings unless all parties agree or the court grants leave. You present your own case.

The WA Minor Case Response Guide includes a defence-drafting worksheet for contractor disputes and an evidence index template designed for trade and building claims.

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