Wilderness Society SA is challenging the national offshore oil and gas authority's environmental approval of Equinor's oil drilling plans for the Great Australian Bight.
The South Australian group's reasons for the legal challenge in the federal court relate to the lack of required consultation with "important and relevant" parties undertaken by Equinor, along with the opposition show by people across the country.
Wilderness Society SA director Peter Owen said the group would be represented by the Environmental Defenders Office in their fight against the approval given to the Norwegian oil company by the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA).
Mr Owen said approval for the ultra-deepwater Stromlo-1 exploration well in the Great Australian Bight was given with tight conditions on December 18, despite no formal consultation with the Wilderness Society or other environmental groups in the Great Australian Bight Alliance, or key indigenous groups, or local governments, about the plans.
He said the legal challenge was not what the group wanted to have to undertake.
"We have engaged diligently and constructively via consultation with other fossil fuel companies seeking approvals in the Bight, including BP. We have engaged diligently and constructively with NOPSEMA. We have consistently requested that Equinor consults with us as an affected and relevant party," Mr Owen said.
"It is patently clear that Equinor has refused to undertake best practice consultation, and it is our view that it didn't even meet the basic regulatory requirements. Our view is that NOPSEMA made an important legal error in accepting Equinor's substandard consultation."
Bunna Lawrie is an elder of the Mirning people, who are the traditional owners of the Great Australian Bight. He said Equinor needed to consult with First Nations people.
"My ancestors and I have looked after the whale, the land and the sea for 50,000 years. We don't want Equinor to put our sea and our place of the whales at risk," Mr Lawrie said.
"We don't want pollution causing destruction and poisoning our sea and land. I do not want my home, my tradition destroyed and lost forever."
Mr Owen said having the views of environmental groups, indigenous custodians, and local governments be "not relevant" in Equinor's application was a concerning precedent being set by the company and NOPSEMA.
"We have no doubt that if Equinor had fully and legally consulted with these parties, its plans would have been better informed and more robust. Instead, it is our view that it now holds an invalid approval," he said.
"Tens of thousands of people have protested against Equinor's Bight plans all around Australia and even in Norway, and on a single day in November there were over 50 paddle-out protests at beaches across the country.
"Opening up a new high-risk frontier oil field when we are hurtling towards catastrophic climate change is madness. Already this summer we have seen massive, heartbreaking and seemingly endless bushfires and toxic smoke fills our cities."
City of Victor Harbor mayor Moira Jenkins said oil exploration had the potential to signifcantly harm environment and economy.
"At a time when we are experiencing more extreme weather events and the world is moving away from a reliance of fossil fuels, the decision to explore for oil in one of our most pristine wilderness spaces makes no sense whatsoever," Dr Jenkins said.
"It makes no economic sense, as it doesn't add anything of substance to either to the Australian economy as a whole, or the economies of Victor Harbor and the South Coast
"It is totally unacceptable that there was no consultation with the council, with the residents of Victor Harbor or any of the communities along the South Coast and Fleurieu, all of who have a special relationship with our coast, the migratory whales, and the marine environment."