Oil from a potential spill in the Great Australian Bight, off South Australia, could reach as far Port Macquarie on Australia's east coast and coat Sydney's beaches, environmental group Greenpeace says.
The organisation has released documents it says were leaked from Norwegian exploration company Equinor which show what could happen if there was a major oil spill in the Bight.
But the Australian Petroleum Production and Exploration Association says the documents detail an absolute worst-case scenario in the event that no action was taken.
Association director Matthew Doman said it was "simply impossible" to imagine oil across the coast in the manner that Greenpeace was suggesting.
"The likelihood of an oil spill is very, very low, but that doesn't mean we don't have to prepare for it," he said.
"We're very proud of our track record of managing our operations in Australian conditions to ensure no environmental harm and we're very confident that we'll do that in the Great Australian Bight."
Equinor is currently preparing an environmental impact statement on its proposal to drill exploration wells in the Bight as part of the approval process.
That's expected to be released for community consultation early next year.
But Greenpeace says the company's draft Oil Pollution Emergency Plan should be the "final nail in the coffin" for drilling in the Bight.
"Not only does it show that oil could drench a previously unimaginable area that would include iconic beaches such as Bondi and Manly, it also shows that oil companies have no plan for stopping such a leak should it occur," senior campaigner Nathaniel Pelle said in a statement on Wednesday.
"The fact that we could see one litre of oil for every square metre of beach as far away from the site as Sydney should convince any politician in Canberra to block these plans.".
