A final call on Woodside's massive gas project has been delayed with the energy giant granted more time to consider federal conditions on cultural heritage and air quality.
Woodside had 10 days to respond to Environment Minister Murray Watt's provisional approval to push out the life of its North West Shelf project in Western Australia but an unspecified extension has since been granted.
Under the proposal, the project - which hosts Australia's biggest gas export plant - will be able to keep operating until 2070.
The tentative approval has angered Indigenous groups fearful it will damage nearby ancient rock art, as well as environmentalists concerned it will hasten climate change.
Protesters took the campaign to the offices of five federal Labor MPs in Perth on Friday where they handed over an open letter opposing the project signed by more than 60 scientists and experts.
The North West Shelf's go-ahead is subject to strict conditions about the impact of air emission levels, provisions the environment minister says will ensure the 60,000-year-old Murujuga Indigenous rock art is not destroyed.
Senator Watt said discussions with Woodside had been constructive and it was not uncommon for proponents in this situation to take a bit longer to respond.
"I can't predict exactly when it will be that Woodside will provide those comments," he told ABC radio on Thursday.
The energy giant confirmed the extended consultation period on Friday.
"Woodside recognises the importance of the matters being addressed by the proposed conditions of the environmental approval including cultural heritage management and air quality," the company said in a statement.
Australian Conservation Foundation climate campaigner Piper Rollins said the public had a right to see the conditions proposed by the minister.
"Australians who are worried about the protection of the ancient Murujuga rock art, which has been nominated for World Heritage listing and is right next door to Woodside's gas hub, deserve to see what Woodside is being allowed to negotiate behind closed doors," Ms Rollins said.
"In addition to the damage to the rock art, extending the NW Shelf gas hub until 2070 locks in decades more climate pollution and will drive demand to open new gas fields."
