A controversial gas project has been given the green light to keep operating for decades to come, provoking an angry response from environmental groups.

New federal Environment Minister Murray Watt on Wednesday approved fossil fuel giant Woodside’s proposal to extend its North West Shelf project in Western Australia.

The approval, which allows Woodside to extend the project’s life from 2030 to 2070, is subject to strict conditions about the impact of air emission levels from the expanded onshore gas plant at Karratha.

The energy company has 10 business days to respond to the proposed decision. Watt said he would consider the response before a final decision was made.

The impact of air emissions on the Murujuga rock art that forms part of the Dampier Archipelago was considered as part of the assessment process, he said.

“I have ensured that adequate protection for the rock art is central to my proposed decision,” he said.

Watt promised to reach a decision by May 31 at the latest. Photo: AAP

Woodside’s proposal to extend the operating life of the project has been under assessment for six years.

The decision came after the release of a report indicating the United Nations will reject Australia’s bid to add the Murujuga rock art to the World Heritage list.

Its integrity was “vulnerable due to industrial emissions, considered the majorly adversely affecting factor for the petroglyphs”, the International Council on Monuments and Sites determined in its report to UNESCO.

An agenda for UNESCO’s meeting in July shows the draft decision will be deferred and the nomination sent back to the Australian government to address the risks to World Heritage values, including “the total removal of degrading acidic emissions currently impacting upon the petroglyphs”.

Australian Conservation Foundation climate campaigner Piper Rollins said the report “clearly identified” the North West Shelf gas hub as the primary risk to the ancient rock art.

“UNESCO is essentially saying to the Albanese government: you can’t have your cake and eat it. You are going to have to choose between World Heritage or Woodside’s toxic gas extension,” she said.

“The two cannot co-exist.”

Greenpeace Australia chief executive David Ritter said Watt’s “terrible decision” brought Woodside’s destructive gas drills one step closer to Scott Reef, a marine ecosystem that is home to threatened species such as pygmy blue whales and green sea turtles.

“The North West Shelf facility is one of Australia’s dirtiest and most polluting fossil fuel projects,” he said.

“The Albanese government’s next decision on whether or not to approve Woodside’s Browse proposal will show Australians the true colours of the government. We urge Minister Watt to stand up for nature and oceans and reject Woodside plans to drill at Scott Reef.”

Independent senator Lidia Thorpe said Watt’s decision “could ignite a climate bomb” and permanently destroy sacred sites, but he hadn’t consulted traditional custodians and had ignored a heritage protection application lodged more than three years ago.

“There is no way to justify this project – not when it will release billions of tonnes of emissions, not when we’re watching Murujuga’s sacred rock art being erased by pollution, and not when communities are suffering the impacts of climate collapse,” Thorpe said.

Watt flew to WA to meet stakeholders but refused to meet Murujuga custodians, she said.

“Choosing Reconciliation Week to push through this decision, while side-lining First Peoples, is not just disrespectful – it’s disgraceful,” she said.

Watt, whose reputation as a dealmaker led to his shift into the environment portfolio, had promised to reach a decision on the extension by May 31.

The federal government twice delayed a final decision until after the election, following approval from the WA government.

Traditional owners have raised concerns about the impact of the expanded project on sacred rock art and launched legal action to try to compel Watt to protect the artwork.

Research released by the Australia Institute showed that emissions from the planned extension would be equivalent to 33 years of Australia’s entire emissions.

-AAP