This precedent has been authored by Dr. Gordon Hughes, Principal, Davies Collison Cave Law.

Introductory note

A contract can, in the absence of a clause to the contrary, be varied either verbally or in writing, and either expressly or implicitly. The existence of a clause stipulating that all variations must be in writing reduces the level of uncertainty in this regard. Nevertheless, the process is not watertight, as a party may still be able to adduce evidence that the requirement for writing was verbally waived by the other party, and that a consequent verbal or implied variation was therefore legally effective (see eg GEC Marconi Systems Pty Ltd v BHP Information Technology Pty Ltd (2003) 128 FCR 1; [2003] FCA 50; BC200300200).