Australia's Federal Environment Minister Peter Garrett appears to be the last hurdle to the project, barring any successful legal action from green groups, after the Western Australia state government this month approved the $50 billion project.

Garrett's decision should be known by September 8, letting Chevron and minority partners Shell and Exxon Mobil, which appear to have ironed out their previous differences, give the long-awaited go-ahead in the middle of the month.

Illustrating Chevron's confidence in the LNG project, it has already awarded more than $2 billion of contracts for early works.

"We think we are very, very close on the environmental permit," Chevron exploration and production vice-president George Kirkland said recently. "We've done all our due diligence and all the project due diligence, to be ready on the decision-making around the economics," he said.