Proportionate liability under part IVAA of the Wrongs Act 1958 (Vic): when is a co-defendant a "concurrent wrongdoer"?

BlueCross Community Care Services Group Pty Ltd v Buxton Constructions (Vic) Pty Ltd & Anor [2026] VSC 581

An interlocutory application has been determined by the Supreme Court of Victoria on whether a defendant, who is alleged to have breached a duty to take reasonable care, can invoke a proportionate liability defence pursuant to Part IVAA of the Wrongs Act 1958 (Vic)¹ (Wrongs Act) against a co-defendant, against whom only non-apportionable claims are pleaded.

In the proceeding, the plaintiff brought an interlocutory application to strike out a defendant's proportionate liability defence, on the basis that the defence is not available at law, and pursuant to r. 23.02 of the Supreme Court (General Civil Procedure) Rules 2025 (Vic)² (Rules).

Associate Justice Goulden dismissed the application and held that the defendant's proportionate liability defence is at least arguable and cannot be characterised as futile.

The decision provides a useful overview of the relevant authorities concerning the issues of apportionment and who qualifies as a concurrent wrongdoer under Part IVAA of the Wrongs Act and pleading the defence. It highlights, however, that there remains doubt and debate within the relevant authorities concerning these issues.

The decision leaves for final determination an issue with significant implications for defendants in multi-party construction disputes.

Lander & Rogers is representing the architect in this matter.

Strike-out application

The proceeding relates to a claim by the owner of an aged care facility for alleged design and construction-related defects at the facility. The owner brings claims against:

• the architect in contract and negligence (i.e. apportionable claims); and
• the builder for breach of absolute contractual warranties (i.e. non-apportionable claims).

The architect has raised a proportionate liability defence under Part IVAA of the Wrongs Act, identifying the builder as a "concurrent wrongdoer" under s 24AH, and seeking to limit its liability to its proportion of the loss and damage suffered by the owner.

The owner applied to strike out the architect's proportionate liability defence on the basis that the defence is not available at law, and so is futile and must be struck out under r 23.02(a) of the Rules.

Owner's position: apportionment requires an apportionable claim against each concurrent wrongdoer

The owner's central contention was that, properly construed, Part IVAA of the Wrongs Act requires each alleged concurrent wrongdoer to be the subject of a pleaded apportionable claim (i.e. a claim involving a failure to take reasonable care). In circumstances where its claims against the builder do not arise from a failure to take reasonable care or otherwise under s 24AF of the Wrongs Act, the builder could not be a concurrent wrongdoer under s 24AH of the Wrongs Act, and the architect cannot raise a proportionate liability defence.

In support of its application, the owner notably relied on the following authorities:

• Tanah Merah Vic Pty Ltd v Owners Corporation No 1 of PS613436, in which the Victorian Court of Appeal concluded that: "the terms in which a claim is framed against a concurrent wrongdoer are an essential determinant of whether the claim can be said to arise from a failure to take reasonable care."³
• LM Investment Management Limited (in liq) (receivers and managers appointed) v BMT & Assoc Pty Ltd, in which Justice Ball stated: "[a]lthough the legislation is not entirely clear, each person who is said to be a concurrent wrongdoer must be a person against whom a claim is or could be made for economic loss in an action for damages arising from a failure to take reasonable care..."⁴

The architect's position: the defence is conventional and at least arguable

The architect's position in response to the owner's application was twofold.

Firstly, the architect contended that its proportionate liability defence pleaded each element of the statutory defence in conventional form⁵ and therefore disclosed a defence for the purposes of r 23.02(a).

The architect emphasised that r 23.02(a) is directed solely to the adequacy of a pleading, not the validity of the claim sought to be pleaded. Ultimately, the strike-out application presents a high hurdle for the owner.

Secondly, on the substantive merits, the architect argued that the definition of a "concurrent wrongdoer" in s 24AH(1) does not require an analysis into the concurrent wrongdoer's legal liability to a plaintiff. The critical factor is simply whether the putative concurrent wrongdoer's acts or omissions caused the same loss or damage, which is a factual as opposed to a legal inquiry.

The architect relied on the following High Court decision in support of its position:

• Hunt & Hunt Lawyers v Mitchell Morgan Nominees Pty Ltd, in which majority remarked: "...[t]here is no express limitation on the nature of the claim which might have been brought by the plaintiff against a concurrent wrongdoer, except the requirement of s 34(2) that the acts or omissions of all concurrent wrongdoers have caused the damage in question".⁶

In Hunt & Hunt, liability was apportioned against fraudsters, illustrating that there does not need to be a pleaded claim alleging a failure to take reasonable care against all concurrent wrongdoers.

The decision

In her decision handed down on 9 September 2026, Associate Justice Goulden held that:

• there is "doubt and debate within the relevant authorities" on the following two questions:
  • whether s 24AH requires an apportionable claim against each concurrent wrongdoer; and
  • whether the availability of Part IVAA is determined solely by reference to the pleadings or if it can be informed by factual findings at trial.
• given the above uncertainties, the architect's proportionate liability defence is "at least arguable" and could not be characterised as futile.
• given that the owner's application raises debatable issues of law and construction, it is appropriate for these issues to be determined at the final hearing.⁷

Conclusion

Although the decision does not create binding precedent on the statutory construction question, it does highlight a significant and evolving question in the Victorian (and Australian) proportionate liability regime and confirms that the courts are likely to consider these issues sufficiently arguable to warrant determination at trial, rather than at summary dismissal.

While the decision reinforces that the court will not exercise its discretion to strike out a pleading under r 23.02(a) where a debatable point of law is raised and will assume the pleading party can establish its allegations at trial, defendants must be alive to the risk that their apportionment defences may be challenged at an early stage and should therefore ensure that their pleadings are defensible both in form and substance.

¹ https://www.austlii.edu.au/cgi-bin/viewdoc/au/legis/vic/consol_act/wa1958111/index.html

² https://www6.austlii.edu.au/cgi-bin/viewdoc/au/legis/vic/num_reg/sccpr2025n85o2025514/s23.02.html

³ (2021) 75 VR 1, [120]

⁴ [2015] NSWSC 1902, [83]

⁵ As identified by Dixon AJA in Utility Services Corporation Ltd v SPI Electricity Pty Ltd (2012) 35 VR 628

⁶ (2013) 247 CLR 613, [18]; s 34(3) Civil Liability Act 2002 (NSW)

⁷ Decision, [19]