Waiver

Commonwealth v Verwayen (1990) 170 CLR 394 at 406. At 406-407 Mason CJ said:

“According to its strict legal connotation, waiver is an intentional act done with knowledge whereby a person abandons a right by acting in a manner inconsistent with that right: Craine v Colonial Mutual Fire Insurance Co Ltd [(1920) 28 CLR 305, at p 326.]; Grundt v Great Boulder Pty Gold Mines Ltd [(1937) 59 CLR 641, at p 658.] However, the better view is that, apart from estoppel and new agreement, abandonment of a right occurs only where the person waiving the right is entitled to alternative rights inconsistent with one another, such as the right to insist on performance of a contract and the right to rescind for essential breach: see Kammins [[1971] AC, at p 883.] This category of waiver is an example of the doctrine of election.

Another category of waiver is one in which a person is prevented from asserting, in response to a claim against him, a particular defence or objection which would otherwise have been available. Here waiver is said to arise when the person agrees not to raise the particular defence or so conducts himself as to be estopped from raising it: see Kammins [[1971] AC, at p 883.].”