The project is a joint venture between Woodside, BHP Billiton, BP, Chevron and Shell. final decision was expected to be made mid 2012 however, the date has been pushed to the first half of 2013.
The state government approved the amendment on Tuesday, Woodside said in a statement.
It originally targeted a start-up of the project by 2011 but is now aiming for first production in 2017.
WA Mines and Petroleum Minister Norman Moore said it was strongly expected that the joint venture would meet the revised timeframe.
Federal Resources Minister Martin Ferguson said the project was complex and the joint venture now had extra time to address the barriers to commercialising it.
