Q. So when you said the plaintiff could not issue a credit, what you're referring to is that you're relying upon an earlier promise to pay the full amount of the invoice; is that the case?
A. We would prefer to have the original invoice paid and then done a credit."
18 In a further statement of 2 September 2008 Mr Lewis, at paragraph 66, summarised Bonfiglioli's claim as being for the particular amounts set forth therein "less the credit for coolers as follows". A little further down in Mr Lewis's calculation was the following item-
"(b) less credit for the two coolers ($2,000 for each cooler)"
19 Although her Honour made no particular finding about the matter, it seems common ground that when the gearboxes were returned to Bonfiglioli's Sydney factory for repair the coolers were removed. It may be accepted that they remained thereafter at Bonfiglioli's factory, though whether property in them passed to Bonfiglioli was never explored at the hearing. The reason for the removal of the coolers seems to have been this. The quotation for the original supply was for gearboxes that had a reduction ratio of 29.3:1. The order issued in response by Concrete Equipment was for gearboxes with a reduction ratio of 19.5:1. Although it may be accepted that gearboxes of the higher reduction ratio need coolers, the ones ordered do not. Even so, Concrete Equipment ordered coolers as well as the lower ratio gearboxes. The evidence is silent about whether the coolers were ever fitted to the lower ratio gearboxes supplied, though Mr Lewis's evidence that the coolers were returned with the gearboxes when they were sent back to Sydney for repair implies that they were. The evidence is silent as to whether any damage to the gearboxes might also have affected the coolers. Mr Lewis was not asked what the invoice price for the coolers was or how he valued them at $2,000 each. Her Honour made no findings about these matters, perhaps because of the way Concrete Equipment had changed its case.
20 On the evidence Counsel for Concrete Equipment asked her Honour to make an allowance by way of set-off of $4,000 for the coolers.
21 In giving judgment her Honour referred to the set-off claims set up by the defence, including that for the coolers, and continued-
"The plaintiff's answer to the defendant's submissions is that as the only remaining aspect of the defence is a defence of set-off and set-off relates to amounts, seemingly claimed for the removal and return of the goods for the period of their repair as from 30 April 2007 to 7 May 2007 and other identified costs, it says that in order to succeed in a defence for set-off s 21 of the Civil Procedure Act 2005 requires the defendant to establish that it is owed a debt by the plaintiff. A debt is defined as a liquidated claim and in order to establish a liquidated claim the defendant must precisely plead and establish a cause of action against the plaintiff which entitles it to set-off amount being claimed. There is no cause of action pleaded in the defence which would entitle the defendant to a set-off as claimed in the defence, that being so, they say on the defendant's own pleadings any defence of set-off must fail."
22 The Civil Procedure Act 2005, to which her Honour was referring, provides as follows-
" 21(1) If there are mutual debts between a plaintiff and a defendant in any proceedings, the defendant may, by way of defence, set off against the plaintiff's claim any debt that is owed by the plaintiff to the defendant and that was due and payable at the time the defence of set-off was filed, whether or not the mutual debts are different in nature.
(2) This section extends to civil proceedings in which one or more of the mutual debts is owed by or to a deceased person who is represented by a legal personal representative.
(3) This section does not apply to the extent to which the plaintiff and defendant have agreed that debts (whether generally or as to specific debts) may not be set off against each other.
(4) This section does not affect any other rights or obligations of a debtor or creditor in respect of mutual debts, whether arising in equity or otherwise.
(5) This section is subject to section 120 of the Industrial Relations Act 1996 .
(6) In this section, debt means any liquidated claim. "
23 It was submitted before this Court that her Honour was not entitled to conclude that there was no cause of action pleaded in the Defence. It was submitted that, however imperfectly, the Defence of set-off was squarely raised.
24 Counsel addressed her Honour on set-off as contemplated by s 21. In this Court set-off under s 21 was not pursued. Counsel relied instead on equitable set-off. It is unclear whether equitable set-off was argued in the Local Court. A defendant may rely on equitable set-off, whether or not the contrary claims are mutual in the sense required by the statutory right in section 21 and irrespective of whether both claims involve liquidated demands. The right of set-off in equity depends on the more general proposition that the contrary liabilities are sufficiently closely connected that it would be inequitable for the plaintiff to be permitted to proceed with its claim without making an allowance for the defendant's claim against it: Roadshow Entertainment Pty Ltd v ACN 053 006269 Pty Ltd (1997) 42 NSWLR 462. In Equititrust v Franks (2009) 258 ALR 388 Macfarlan JA said at [59]-
" I mention in conclusion in relation to s 21 that that section speaks of a defence of set-off being "filed". I do not regard this reference as precluding a defence of set off being raised where, although not contained in a filed form of defence, the defence, as here, is litigated at the hearing."
25 In AWA Limited v Exicom Australia Pty Ltd (1990) 19 NSWLR 705 at 711, Giles JA said-
"Thus the effect of an equitable set-off is not just a restraint upon enforcement of a judgment, but a restraint which if imposed will have important consequences if (for example) the plaintiff be insolvent. Its effect is not just procedural: see Derham, Set-Off (1987) (at 47-52). There must be something additional to the fact of a cross-demand to cause the court, in the exercise of its equitable jurisdiction, to require the plaintiff to set-off against his claim the claim of the defendant.