Chevron said it would consider a massive expansion of its Gorgon natural gas project off the Western Australian coast in about 18 months, only hours after the US oil group and its partners approved a A$43bn (US$37bn) initial spending programme.

The estimated 40,000bn cu ft of natural gas contained in the Gorgon fields is a globally significant resource that will play a role in servicing the long-term energy needs of fast-growing economies, led by China and India, as well as Japan and South Korea.