The National Gas Access (WA) Act 2009 (NGA) came into effect 1 January 2010 and amends and implements the National Gas Law (NGL) in Western Australia. The amended NGL as it is implemented in Western Australia is referred to here as the NGL (WA). The NGA also gives effect to the National Gas Rules as relevant to gas access regulation. The legislation implements a national gas access regime that replaces the national Gas Pipeline Access Law implemented in Western Australia by the Gas Pipeline Access (WA) Act 1998.

A key objective of the new national gas access legislation is to implement a uniform national regime, and as a guide to the access arrangement process in Western Australia, interested parties can refer to the Australian Energy Regulator's Access Arrangement Guideline.

The Economic Regulation Authority is responsible for regulating third party access to regulated gas pipelines including approving access arrangements, ring fencing and associate contracts.