"[44] A payment claim under the Act is, in many respects, like a Statement of Claim in litigation. In pleading a Statement of Claim, the plaintiff sets out only the facts and circumstances required to establish entitlement to the relief sought; the Statement of Claim does not attempt to negative in advance all possible defences to the claim. It is for the defendant to decide which defences to raise; the plaintiff, in a reply, answers only those defences which the defendant has pleaded.
[45] In my opinion, a payment claim under the Act works the same way. If it purports reasonably on its face to state what s 13(2)(a) and (b) require it to state, it will have disclosed the critical elements of the claimant's claim. It is then for the respondent either to admit the claim or to decide what defences to raise.
[46] An assertion that service of a payment claim is prohibited under s 13(4) or (5) is like a defence in bar. For example, in the case of an action at law or in equity founded upon an oral contract for an interest in land it is open to a defendant to elect whether to raise a defence in bar founded on the Statute of Frauds. Similarly, it would be open to a respondent served with a payment claim under the Act to elect whether to raise a defence in bar that service of the claim is prohibited by s 13(4) or (5). A respondent to a payment claim may have a reason for electing not to raise such a defence: the payment claim may raise for determination an issue which will inevitably have to be determined in subsequent payment claims and the respondent may wish the issue to be resolved sooner rather than later.
[47] However, if the respondent does elect to raise a defence in bar founded on s.13(4) or (5), adjudication of that defence will require examination of the relevant terms of the contract, possibly the facts relating to the work performed and the time of performance and possibly also the content of previous payment claims. That examination may well be contentious and may involve issues of fact and law upon which minds may legitimately differ.
[48] In my opinion, the scheme of the Act in general and of s.13 and s.14 in particular requires that a defence in bar to a payment claim founded on s. 13(4) or (5), like any other defence said to defeat or reduce the claim, must be raised in a timeously served payment schedule. If it is not, then the defence may not be relied upon to set aside or restrain enforcement of the adjudication determination as a nullity, nor may it be relied upon as a defence to entry of judgment under s.15(4) of the Act.
[49] In my opinion, these conclusions are consistent with, and are inherent in, the reasoning in Brodyn and they are not contrary to the majority decision in Nepean. They are also in conformity with the general approach to the determination of invalidity of a payment claim under s.13(4) and (5) taken by McDougall J in Energetech Australia Pty Ltd v Sides Engineering Pty Ltd [2005] NSWSC 801, at para 25, by Campbell J in Lifestyle Retirement Projects No 2 Ply Ltd v Parisi Homes Pty Ltd [2005] NSWSC 705, at para 19, and by Campbell J in Energetech Australia Pty Ltd v Sides Engineering Pty Ltd [2005] NSWSC 1143 at paras 87-90."