Senator Dorinda Cox has thrown her support behind Tiwi Traditional Owners who have filed human rights complaints against some of Australia's biggest banks.

Six Tiwi Traditional Owners and a Larrakia Traditional Owner have filed human rights complaints with Australian banks ANZ, CBA, Westpac and NAB upon learning these banks provided loans for the Barossa gas project.

Senator Cox, the Australian Greens spokesperson for Resources and First Nations, said this is a call to action for people to hold these banks accountable to their own human rights policy.

"These banks have human rights policies that are in line with international human rights standards. That means they should be assessing and avoiding human rights breaches when funding companies and projects," she said.

"Free, Informed and Prior Consent was never given by the Tiwi Traditional Owners, yet their sacred sites and Sea Country have been put under serious threat.

"We will not stand by and allow companies to disregard human rights while destroying First Nations cultural heritage and way-of-life."

At the time the loan was finalised in September 2022, Tiwi Islanders were already fighting the Barossa gas project and petroleum regulator NOPSEMA in the Federal Court of Australia.

Munupi senior Lawman Dennis Tipakalippa and other residents on the Tiwi Islands launched legal action in June 2022, against NOPSEMA over their handling of the Barossa project.

The court found NOPSEMA had failed in their approval processes and should not have approved Santos' drilling plans. The company appealed the court's decision but the Federal Court ruled in favour of the Tiwi Islanders.

One of the complainants, Malawu clan leader Therese Wokai Bourke, said the banks need to change their approach to business.

"We want the banks to re-think what they're doing," she said.

ANZ contributed the equal highest amount of US$65 million (AUD$97 million) to the loan.

Vidhya Karnamadakala, associate lawyer from Equity Generation Lawyers representing the Traditional Owners, said ANZ need to follow their own human rights policies.

"The Traditional Owners submitting the complaints do not want the Barossa project or the DLNG extension to go ahead. They have a right to say no," she said.

"ANZ has a human rights policy to ensure it avoids funding projects like Barossa. ANZ must show its shareholders, customers and the community that its human rights commitments are not just window dressing."

Senator Cox said she will be writing to regulator ASIC urging it to independently investigate these four banks.

"(My jobs) is to look at who else is funding the US$1billion into the Barossa gas field and ask them a question about their human rights policies," she said.

"Ask them about whether they think consent has been obtained from Traditional Owners on those lands and whether they actually think they are in breach.

"Because I think what they will find is, this contravenes international law and the obligation which they have to operate their businesses here within Australia."

A spokesperson from ANZ said they are considering the matter.

"ANZ will consider the matter in line with the processes under our Human Rights Grievance Mechanism," they said.

A spokesperson for NAB said due to client confidentiality they are unable to comment on individual customers but have received a grievance complaint.

"NAB confirms it has received the grievance complaint and is working through its contents," a spokesperson said.

Westpac and CBA were also been contacted by the National Indigenous Times for a comment.

Santos have declined to comment at this time.

Alongside the four Australian banks, other banks investing in the Barossa gas project include ING (Netherlands), DNB Bank (Norway), Citigroup (USA), Royal Bank of Canada (Canada), DBS Bank (Singapore), MUFG (Japan) and Mizuho (Japan).