151 A further argument made by Ms Wilkinson was that when Mr Xiao agreed on 9 May 2008 to Mr Japardi's proposal to make a payment of $1,000 towards the arrears of rent, he waived on Mr and Mrs Pham's behalf any right of termination that they then possessed. She relied for this proposition on the judgment of Macready AsJ in Gumland v Duffy [2006] NSWSC 10 at [102]. In that paragraph, his Honour quoted the following passage from the judgment of Campbell J in Spathis v Hanave Investment Co Pty Ltd [2002] NSWSC 304 at [118]:-
It is well enough established that, if a landlord is entitled to terminate a Lease for breach of covenant, and he or she knows of that breach but subsequently accepts rent, that is a waiver of the landlord's rights to terminate the Lease on the basis of that breach. The principles are succinctly summarised by Windeyer J in Owendale Pty Ltd v Anthony (1967) 117 CLR 539, at 556.
A waiver in this sense is more properly understood as an election. The essence of the doctrine, in cases between landlord and tenant, is that where a Lease contains a provision for forfeiture and a right of re-entry upon breach of a covenant by the lessee, then, upon a breach occurring, the lessor can either take advantage of his right of forfeiture and re-entry or waive this and treat the Lease as still subsisting. If, with knowledge of a breach, giving him a right of re-entry, he does an act inconsistent with his avoiding the Lease, he is deemed to have elected not to avoid it. Anything which a landlord does or says which is an unequivocal recognition of the continued existence of the Lease when he is aware of facts which would have given him a right of re-entry will amount to a waiver of that right. One act which, by the common law, is always regarded as unequivocal, and therefore necessarily a waiver of a right of re-entry on account of a breach of covenant by the lessee, is the lessor's acceptance, with knowledge of the fact of the breach, of rent accrued due after the breach. Apart from any special term in the Lease… or any statutory modification of the common law, acceptance of rent due in respect of a current period is an obvious recognition of a tenancy then subsisting….