A legal challenge against plans to drill for oil in the Great Australian Bight has been launched in the Federal Court.

Key points: Equinor was given conditional approval to drill for oil in the Great Australian Bight last month

Equinor was given conditional approval to drill for oil in the Great Australian Bight last month The Wilderness Society is challenging the decision in the Federal Court

The Wilderness Society is challenging the decision in the Federal Court It said Equinor failed to consult adequately with environmental organisations

The Wilderness Society is taking the national regulator — the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) — to court after it granted conditional environmental approval to Norwegian oil company Equinor to conduct drilling.

The society alleges Equinor did not consult "important and relevant parties", which it said was required by regulations.

Equinor, which is majority owned by the Norwegian Government, plans to drill its Stromlo-1 exploration well 372 kilometres south of the Nullarbor coastline, off South Australia.

Last month's environmental approval will allow the company to drill 24 hours a day for about 60 days between November and April in either 2020–21 or 2021–22.

Drilling in the Bight has been fiercely opposed by environmental groups concerned about the threat of a catastrophic oil spill.

Sea Shepherd Australia's Jeff Hansen, Mirning elder Bunna Lawrie, the Wilderness Society's Peter Owen and Holdfast Bay Mayor Amanda Wilson at the launch of the legal action. ( ABC News: Stacey Lee )

Consultation not sufficient, group claims

NOPSEMA's environmental approval process took eight months, with the authority reviewing more than 30,000 submissions and twice requiring Equinor to modify and resubmit its plans.

Equinor plans to use a mobile offshore drilling unit, supported by three ships and two helicopters.

Environmentalists say drilling in the Bight poses a major threat to marine life such as the leafy sea dragon. ( Supplied: Richard Robinson/Greenpeace )

The Wilderness Society is a member of the Great Australian Bight Alliance, a group of environmental organisations along with the Mirning Indigenous people, whose traditional lands cover far south-eastern Western Australia.

At the announcement of its court action in front of the Federal Court building in Adelaide's CBD, the society said Equinor refused to formally consult with it or other environment groups on its plans.

It also accused the oil company of refusing to formally consult with "key Indigenous groups and local governments".

"The precedent that has been set by NOPSEMA's approval of Equinor's environment plan means that in the future, environment groups, traditional owner groups, local governments, aren't relevant people for proposals like this to be involved in consultation," Wilderness Society SA director Peter Owen said.

"That is a precedent that cannot be allowed to be set in this country."

An Equinor spokeswoman said it was "not appropriate for Equinor to comment on a legal matter before the courts".

NOPSEMA spokesman Nicholas Page said the authority was "not in a position to provide further comment on the court action at this stage".

"NOPSEMA has addressed the key matters raised through the assessment of Equinor's environment plan," he said.

Aboriginal people part of action

Mirning elder Bunna Lawrie said there had been no discussions with his people over the drilling, saying he and his ancestors had "looked after the whale and the sea for over 50,000 years and more".

"There was no consultation to the Mirning elders, it's very disrespectful," he said.

"We did not give permission and we did not give consent to anyone or anybody to do what they want to do there now."

When rejecting Equinor's draft plans in June, NOPSEMA asked the company to provide more information about why it did not consider the Wilderness Society, Sea Shepherd Australia, the Mirning and Ngarrindjeri people or Adventure Bay Charters as parties which had to be consulted.

An adult southern right whale with a calf in the Great Australian Bight. ( Claire Charlton )

Equinor noted in its final environmental plan that it had met with Barngarla, Narungga, Nauo and Wirangu people during consultation.

However, the company said "the Mirning and Ngarrindjeri peoples did not claim they were relevant persons during the public comment process" — an assertion which was rejected by NOPSEMA.

"This is not considered a sufficient reason to determine that the Mirning and Ngarrindjeri people are not relevant persons, and is incorrect in the case of the Ngarrindjeri people," NOPSEMA said in November, before environmental approval was granted in December.

"It is also noted that the Mirning people have repeatedly and publicly expressed their desire to be consulted."