Principles
36The principles applicable in cases such as this where the sole issue left for determination is whether orders for costs should be made are conveniently summarised in ONE.TEL Ltd v Deputy Commissioner of Taxation [2000] FCA 270 by Burchett J:
"5 It is accepted that, in a case which terminates before there has been a hearing, the Court should not resolve the issue of costs by engaging in something in the nature of a hypothetical trial: Australian Securities Commission v Aust-Home Investments Ltd (1993) 44 FCR 194 at 201; Re The Minister for Immigration and Ethnic Affairs of the Commonwealth of Australia; Ex parte Lai Qin (1997) 186 CLR 622 at 624. But this does not mean that the Court can never make an order for costs. Often, it will be unable to do so; but in other cases an examination of the reasonableness of the conduct of the parties, respectively, may provide the basis of an order, or "a judge may feel confident that, although both parties have acted reasonably, one party was almost certain to have succeeded if the matter had been fully tried", as McHugh J put it in Ex parte Lai Qin at 625. His Honour added:
"If it appears that both parties have acted reasonably in commencing and defending the proceedings and the conduct of the parties continued to be reasonable until the litigation was settled or its further prosecution became futile, the proper exercise of the cost discretion will usually mean that the court will make no order as to the cost of the proceedings."
Although his Honour thought this would "usually" be so, he made it clear that he was not laying down an invariable rule. At the beginning of his discussion of the applicable principles (at 624), he referred to the discretionary nature of the power to order costs, and to the "general rule [that] the successful party is entitled to his or her costs", and he said:
"In an appropriate case, a court will make an order for costs even when there has been no hearing on the merits and the moving party no longer wishes to proceed with the action."
As Sackville J pointed out in Rizal v Minister for Immigration and Multicultural Affairs [1999] FCA 334 at para 16, the remarks made by McHugh J evince "a somewhat more flexible approach" than that taken by the Court in Gribbles Pathology Pty Ltd v Health Insurance Commission (1997) 80 FCR 284 at 287, when it suggested that "there will be very few cases where the issues will be sufficiently clear, in the absence of a hearing, for an order for costs to be made in favour of a party." What is well established is that frequently the determining factor will be the reasonableness of the conduct of the parties, a matter which was emphasized in each of the decisions I have cited, and also in Reddy v Hughes (1996) 37 IPR 413; Sun Zhan Qui v Minister for Immigration and Ethnic Affairs [1999] FCA 119; and Australian Securities Commission v Berona Investments Pty Ltd (1995) 18 ACSR 772. In the last case, Cooper J commented (at 774), concerning the principles laid down in Australian Securities Commission v Aust-Home Investments:
"These propositions are of assistance in focusing attention upon some of the relevant circumstances which should be considered in the exercise of the discretion to award costs where proceedings do not proceed to a final hearing. However they are not the only circumstances; nor are they intended to limit the discretion."
6 In my opinion, it is important to draw a distinction between cases in which one party, after litigating for some time, effectively surrenders to the other, and cases where some supervening event or settlement so removes or modifies the subject of the dispute that, although it could not be said that one side has simply won, no issue remains between the parties except that of costs. In the former type of case, there will commonly be lacking any basis for an exercise of the Court's discretion otherwise than by an award of costs to the successful party. It is the latter type of case which more often creates problems, since there may be difficulty in discerning a clear reason why one party, rather than the other, should bear the costs. In Ex Parte Lai Qin, McHugh J was careful to state (at 624) that the principles with which he was concerned were those that "govern an application for costs when a party elects not to pursue an action because he or she has achieved the relief sought in the action either by settlement or by extra-curial means"."
37Relevant to the issue of mitigation are the principles explained in Owners - Strata Plan No. 76674 v Di Blasio Constructions Pty Ltd [2014] NSWSC 1067 by Ball J:
"44 In the case of building contracts, it is also generally accepted that the owner must give the builder a reasonable opportunity to rectify any defects. Often, of course, the building contract itself requires the owner to repair defects or sets out a procedure by which defects are to be made good: see, eg, Bitannia Pty Ltd v Parkline Constructions Pty Ltd [2009] NSWSC 1302; (2010) 26 BCL 335. But, even if it does not, the owner is required to give the builder an opportunity to minimise the damages it must pay by rectifying the defects, except where its refusal to give the builder that opportunity is reasonable or where the builder has repudiated the contract by refusing to conduct any repairs: see J Bailey, Construction Law, (Vol II, 2011, Informa Law) at [14.109]; Cassidy v Engwirda Construction Co (No 2) [1968] Qd R 159 (reversed on other grounds in Cassidy v Engwirda Construction Co (No 2) [1968] QWN 47 (HC); (1968) 42 ALJR 168). That obligation may be an aspect of the duty to mitigate, since it may be less expensive for the builder rather than a third party to rectify the defects, particularly if the builder is still on site. But the obligation is not simply an aspect of the duty to mitigate. The cost to the builder of undertaking the repairs is likely to be less than the amount that a third party would charge the owner for the same work. In that case, the owner is not mitigating its loss, but rather the builder's damages.
45 The question of what is reasonable depends on all the circumstances of the particular case. One relevant factor is what attempts the builder has made to repair the defects in the past and whether, in the light of the builder's conduct, the owner has reasonably lost confidence in the willingness and ability of the builder to do the work: see A Chambers, Hudson's Building and Engineering Contracts, (12th ed, 2010, Sweet & Maxwell) at [4-144]; Eribo v Odinaiya [2010] EWHC 301 (TCC) at [70].
46 It is for the defendant to prove that the plaintiff has acted unreasonably. It is not for the plaintiff to prove that it acted reasonably: TC Industrial Plant Pty Ltd v Robert's Queensland Pty Ltd [1963] HCA 57; (1963) 180 CLR 130 at 138; Burns v MAN Automotive (Aust) Pty Ltd [1986] HCA 81; (1986) 161 CLR 653 at 673 per Brennan J; TCN Channel 9 Pty Ltd v Hayden Enterprises Pty Ltd (1989) 16 NSWLR 130 at 158 per Hope JA (with whom Priestley and Meagher JJA agreed); Karacominakis v Big Country Developments Pty Ltd [2000] NSWCA 313 at [187] per Giles JA (with whom Handley and Stein JJA agreed).
47 The obligation not to act unreasonably does not come to an end once court proceedings have commenced. But the existence of court proceedings is relevant to the content of the obligation. Once there is a dispute concerning whether a plaintiff has failed to mitigate its loss, or failed to act reasonably in some other respect, the plaintiff is entitled to have that question tested in court; and the mere fact that it does so is not itself evidence that it has failed to act reasonably. As Oliver J explained in Radford v de Froberville [1978] 1 All ER 33; [1977] 1 WLR 1262 at 1287E-F:
[O]nce proceedings have been commenced and are defended, I do not think that the defendant can complain that it is unreasonable for the plaintiff to delay carrying out the work for himself before the damages have been assessed, more particularly where his right to any damages at all is being contested, for he may never recoup the cost. If, therefore, the proceedings are conducted with due expedition, there seems to me to be no injustice if, by reason of the time that it takes for them to come to trial, the result of inflation is to increase the pecuniary amount of the defendant's ultimate liability... "
38Absent clear words in a contract which give the builder the right to remedy the defective work, the owners' failure to give the builder the opportunity to do so would be relevant to an issue of mitigation, to be taken into account in the overall assessment of damages. If the builder proved that the owner had acted unreasonably, the owner may be liable to some reduction in the damages which would ordinarily be awarded (Keating On Construction Contracts: 8th Edition para 10-023).
39The Court's discretion to order the payment of interest on costs is under the Civil Procedure Act (2005) NSW which, relevantly, provides:
"101 Interest after judgment
(4) The court may order that interest is to be paid on any amount payable under an order for the payment of costs.
(5) Interest under subsection (4) is to be calculated, at the prescribed rate or at such other rate as the court may order, as from:
(a) the date or dates on which the costs concerned were paid, or
(b) such later date as the court may order."
40The approach to be taken on the issue of interest on costs was stated in Illawarra Hotel Company Pty Ltd v Walton Construction Pty Ltd (No.2) [2013] NSWCA 211; [2013] 84 NSW LR 436:
"38 A party who contends that there should be an order for interest on costs must do more than point to the fact that the proceedings were protracted and that it had to outlay moneys on its own costs over a long period. The reasons for the protracted nature of the proceedings are of obvious relevance. To take a hypothetical example, one can imagine a case in which one party deliberately seeks to prolong proceedings with an eye to some collateral benefit of its own for which it is quite happy to pay the price of being out of the money it progressively outlays for costs. That hypothetical case can be contrasted with another in which a party has made strenuous effort to expedite matters and to avoid all delay with a view to the earliest possible trial but has been frustrated in those efforts by actions of the other party. A middle course is where each party acts with reasonable diligence and dispatch but the nature of the proceedings and their subject matter is such as to prolong them. A court might well take different attitudes to applications for interest on costs in these hypothetical cases.
39 This litigation was, of its nature, time-consuming and exacting. Building cases often descend into what, to the outside observer, seems to be tedious analysis of a vast myriad of minutiae. In the absence of some sufficiently clear explanation of the reasons why this litigation proceeded as it did, in a timing sense, there would be no sound basis for exercise of the discretion concerning interest on costs, even if it were now exercisable by this Court in relation to the costs in the court below."