Controversial gas project hinges on 11th-hour talks

Federal and state politicians have started talks on the possible extension of a massive gas project which faces fierce opposition from conservationists.

Environment Minister Murray Watt arrived in Perth on Tuesday, ahead of a meeting with Western Australia's Labor government, along with industry, conservation and Indigenous groups, about Woodside's North West Shelf gas project.

The energy company's proposal to extend the operating life of its gas project from 2030 to 2070 has been under assessment for six years, and a decision has been delayed twice.

Senator Watt has said he intends to approve or reject it by the May 31 deadline.

WA Premier Roger Cook's government has approved Woodside's plan, with the final tick of approval needed from the federal government.

"We'll be urging him to make a decision in relation to the North West Shelf gas extensions as soon as possible, but in a manner which provides for a safe and legally sound decision," the premier told reporters.

Philanthropist Janet Holmes a Court weighed in on the debate, zeroing in on the potential impact of the extension on Indigenous rock art near the Karratha Gas Plant in operation since 1984, labelling it vandalism.

"I really urge the minister to visit the site and to consider the consequences of permitting Woodside to extend ... the pollution that will destroy this ancient, important and significant site," she said.

Ms Holmes a Court, whose son is Climate 200 founder Simon Holmes a Court, expects court challenges if the extension is granted.

Australian Conservation Foundation campaigner Piper Rollins said the extension decision was a climate test for the Albanese government.

"Woodside is proposing to drill, extract and export gas until 2070, which is wildly inconsistent with Australia's net-zero by 2050 commitment, and is deeply inconsistent with Labor's own mediocre climate ambition," she said.

The foundation will meet with the Senator Watt during the week.

Greenpeace campaigner Geoff Bice called on the minister to reject the application.

"We know from Woodside's plans that the main reason they want that extension to go on is to allow drilling for gas from underneath the Scott Reef," he said.

"We're confident that when the minister looks at the full evidence that he will be able to make that decision to knock back North West Shelf."

Australian Marine Conservation Society chief executive Paul Gamblin warned approving the extension could "haunt us forever".

Woodside's project is on and offshore the Burrup peninsula in northwest WA, known as Murujuga, which is nominated for UNESCO World Heritage listing as it contains the world's largest collection of Aboriginal rock art.

WA Greens MP Sophie McNeill called on the state government to release a report about the rock art.

"We know that they've been sitting on it since December last year, and it is critical that before the decision on the North West Shelf extension is made, they release it," she said