More than 100 activists have braved the chilly waters off Oslo in a paddle-out protest against oil drilling proposed for the Great Australian Bight.

Key points: Equinor is seeking approval to drill for oil off the Great Australian Bight

Equinor is seeking approval to drill for oil off the Great Australian Bight The Norwegian Government has a 67 per cent majority stake in the company

The Norwegian Government has a 67 per cent majority stake in the company Protesters say drilling is too risky but Equinor says it can be done safely

Norwegian oil company Equinor wants to search for oil off the coast of South Australia by the end of 2020, but needs approval from the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) to begin.

Local Norwegians joined an Australian delegation of Indigenous and environmental activists who had flown in to protest ahead of Equinor's annual general meeting in Oslo on Wednesday.

Organiser Peter Dawson told the ABC it was the largest paddle-out demonstration ever held in Norway, even though the water was only 8 degrees Celsius.

"It was incredibly moving and heartening to see Norwegians not only paddling side by side with Australians, but chanting 'fight for the Bight' as loud as they possibly could," the Wiradjuri man said.

"I was in the water, surrounded by hundreds of Norwegian surfers splashing and chanting, with Mirning Aboriginal elder Bunna Lawrie in the centre, singing in his traditional language."

Much of the biodiversity in the Bight is found nowhere else on Earth.

The Norwegian Government has a 67 per cent majority stake in Equinor.

"Norwegians are concerned that their state-owned oil company is planning to drill in a pristine marine wilderness area in Australia despite the obvious risks and the widespread community opposition," Mr Dawson said.

Mirning people are the traditional owners of the land that borders the Bight, and Mr Lawrie met with Norwegian indigenous Sami people, to discuss their shared experiences with the industry in the two countries.

"The message to Equinor today was clear: this is the wrong project at the wrong time in history," Mr Dawson said.

"The Bight is an utterly inappropriate place for risky deep-sea oil drilling and we can't be opening up new frontier oil fields while the world's scientists are telling us we need to transition away from fossil fuels."

Mirning Aboriginal elder Bunna Lawrie speaks to a crowd of protesters in Oslo. ( Supplied: Hallvard Kolltveit )

Environmental risks debated

Similar protests were held in the Adelaide suburb of Brighton earlier this month and at Victor Harbor and Torquay in March.

The issue has been front and centre in South Australia's two marginal seats: Boothby — which includes Brighton along with Glenelg — and Mayo — which includes Kangaroo Island and the Fleurieu Peninsula.

In November, the ABC revealed an internal draft emergency plan prepared by Equinor that showed oil could reach as far as Port Macquarie under a "worst credible case" scenario.

But an environmental report released by Equinor earlier this year said it had protections in place to ensure that situation never eventuated.

"Equinor has implemented strict barriers to prevent a spill, [prepared] intervention and mitigation measures as backup and is confident that the risk has been reduced," the report stated.

Protesters at the paddle-out in a fjord off Oslo in Norway. ( Supplied: Hallvard Kolltveit )

Equinor said after two years of research, consultation and preparation, its environmental plan showed it could drill safely in the Bight.

Australian country manager Jone Stangeland said the company had opened up its environment plan for public comment and would listen to any feedback.

"We noted the protest held in Oslo on the weekend. We believe everyone is entitled to voice their opinion, but we encourage people to read our environment plan and become informed about our plans for safe operations," he said.

"There are some organisations who continuously misrepresent both the risk and consequences of our planned activities, and we call on all parties involved in the public debate to hold themselves to a high standard of factual information."

According to a report commissioned by Australian Petroleum Production and Exploration Association, Equinor's plans to drill in the Bight could bring up to 1,500 jobs to South Australia over the next 40 years.

Federal election issue in marginal seats

Opposition Leader Bill Shorten has promised to commission a study into the environmental consequences of an oil spill in the Great Australian Bight.

Mr Shorten said he wanted to know more about what would happen if things went wrong.

"If I form a government, one of my first decisions will be to get an oil spill study," he said last week.

"I want to understand the consequences of an oil spill in the Bight."

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Centre Alliance Mayo MP Rebekha Sharkie wants the Bight heritage-listed to prevent drilling.

"I have a bill in the Parliament for national heritage-listing in the Bight, and we need to see one of the major parties step away from big oil and recognise there's a multitude of industries in SA that are at risk," she said.

Liberal candidate Georgina Downer said she was looking forward to the National Offshore Petroleum Safety and Environmental Management Authority making a decision on the project.

"Equinor really has to do a lot better in convincing South Australians that there is something in this project for us," she said.

State Labor MP Leon Bignell travelled to Norway last week to meet with the Norwegian Government.

He said it was an issue worrying a lot of people in South Australia.

"It has been for millions of years a marine environment out there where 85 per cent of the marine life just doesn't exist anywhere else on Earth," he said.

"At the moment there is no risk of an oil spill, but as soon as you go out there and start drilling, there is a risk."