(8) whether the proprietors' conduct debarred them from obtaining the relief sought. (This, of course, was an issue raised by the builder, not by the proprietors.)
Abuse of process and issue estoppel in the context of the Act
18 Before I turn to the issues, I will refer to the authorities on which the parties relied, and set out my understanding of the principles to be derived from them.
19 The doctrines of estoppel by res judicata and issue estoppel are founded on the principle that controversies, once resolved by a court or tribunal of competent jurisdiction, should not be reopened except in limited circumstances: D'Orta Ekenaike v Victoria Legal Aid (2005) 223 CLR 1 at 17 [34]. Estoppels may arise from the decisions of judicial tribunals, domestic tribunals (including arbitrators and others given authority, by consent of the parties or otherwise, to hear and determine disputes) and in some cases administrative tribunals. See Spencer Bower, Turner and Handley, Res Judicata (third edition, 1996) at 25; and, as to administrative tribunals, the judgments of Barwick CJ and Gibbs J (with whom, on this point, Menzies and Stephen JJ agreed) in The Administration of the Territory of Papua and New Guinea v Daera Guba (1973) 130 CLR 353 at, respectively, 403 - 404 and 453 - 454.
20 In Dualcorp Pty Ltd v Remo Constructions Pty Ltd [2009] NSWCA 69, the Court of Appeal considered a situation where a builder, having obtained adjudication on four invoices and been dissatisfied with the outcome, made a further adjudication application based on those four invoices and two others. The proprietor did not serve a payment schedule. The builder sought summary judgment in the District Court. The primary judge declined to give summary judgment because to do so "is barred because of principles akin to res judicata at least or constitutes an abuse of process" (see her Honour's reasons quoted by Macfarlan JA at [31]). The Court of Appeal upheld her Honour's decision.
21 Macfarlan JA, with whom Handley AJA agreed, held that on the proper construction of the Act, an adjudicator's determination possessed a sufficient degree of finality to raise an issue estoppel precluding subsequent reagitation (in another adjudication) of the same issue: see, in particular, at [68] to [70]. However, as Macfarlan JA pointed out at [68], an adjudicator's determination does not attract the principles of res judicata, because "the analogy between an adjudicator's determination and a completed cause of action is an incomplete one". Thus, as his Honour said (again at [68]), "[i]t is best that the applicable principles be recognised to be those of issue estoppel".
22 The conclusion, that the determinations of adjudicators attract the principles of issue estoppel, was based upon considerations of finality. This is apparent from the review of those principles undertaken by Macfarlan JA: see (under the general law) at [42] to [50] and (under the Act) at [51] to [62]. That review led his Honour to the conclusion that the legislature intended to render the determinations of adjudicators "relevantly conclusive": i.e., conclusive as to entitlements to progress payments. As his Honour said at [60], where a dispute is resolved by determination, the intention of the Act is that the "determination… be final and binding between the parties as to the issues determined, except to the extent that the Act allows the determination to be revisited".
23 Further, Macfarlan JA said that to permit reagitation, in a subsequent adjudication, of issues decided in an earlier adjudication might amount to abuse of process: see, in addition to the paragraphs that I have referred to, his Honour's reasons at [71]. I return to this at [28] below.
24 Allsop P agreed that reagitation, in a subsequent adjudication, of issues decided in an earlier adjudication might be an abuse of process: see his Honour's reasons at [2], [13] and [16]. His Honour would have reserved consideration of the applicability "of principles of estoppel to prevent any apparently abusive operation of the Act not specifically covered by" its relevant provisions: see, again, at [16].
25 In Perform (NSW) Pty Ltd v Mev-Aus Pty Ltd [2009] NSWSC 416, Rein J held at [41] that the ground of the decision of the majority (Macfarlan JA and Handley AJA) in Dualcorp was based on estoppel.
26 In The University of Sydney v Cadence Australia Pty Limited [2009] NSWSC 635, Hammerschlag J was faced with a submission that the majority holding in Dualcorp on issue estoppel was obiter. His Honour said at [46] that he had "significant doubt" that it was. I agree, as I agree with the analysis of Rein J on this point. In my view, Macfarlan JA and Handley AJA decided the matter on the basis that there was an issue estoppel even though an adjudicator's determination could not give rise to res judicata. I think, reading the judgment of Macfarlan JA, it is clear that his Honour decided the matter on the basis of issue estoppel, and that what his Honour said about abuse of process was obiter.
27 In any event, this is in my view academic, because even if the majority view on issue estoppel were obiter, I agree with Hammerschlag J in Cadence at [47] that it is for someone other than a first instance judge to say that their Honours' view is plainly wrong, and should not be followed.
28 Rein J concluded in Perform that there was an issue estoppel, and that there was also an abuse of process, because the builder in that case had sought to reagitate, in a subsequent adjudication, claims decided by an earlier adjudication. In those circumstances, his Honour said, the Court could and should intervene to prevent the later adjudication from proceeding. His Honour gave five reasons for that at [47]. I paraphrase those reasons as follows: