Six Tiwi Islands traditional owners and one Larrakia traditional owner have filed human rights complaints with 12 Australian and international banks, imploring the financial institutions to cut a $1.5 billion loan to Santos in hopes of stopping its Barossa offshore gas project, their lawyers have said.

Law firm Equity Generation Lawyers associate Vidhya Karnamadakala, said the firm, which handles climate-related cases, and is representing the Indigenous group, said the group wants the banks to back out from the $1.5 billion loan on the Barossa project, and ignore a proposed loan for the Darwin LNG project at Middle Arm.

Ms Karnamadakala said traditional owners had deep spiritual connections to the Tiwi Islands and Larrakia country, and the Santos project would disrupt their songlines, sacred sites and cultural practices.

She said the ANZ had a human rights policy founded on the United Nations guiding principles for business and human rights which require banks to avoid contributing to adverse human rights impacts when they lend money to companies.

For years, both traditional owners and environmental groups have been protesting the $3.6 billion project in the Northern Territory.

In September last year, at the time the loan was arranged and finalised, Tiwi Islanders were fighting the Barossa project in the Federal Court and Santos was forced to suspend drilling operations on the Barossa project after a Federal Court judge ruled that the environmental approval gained by the company was not considered valid since it had not properly consulted the Munupi clan.

Last December, the full Federal Court rejected the company’s appeal against the decision saying Santos had failed to consult Tiwi islanders over the project’s environmental protection plan.

“I aim to stop whoever is supporting Santos with all the funds. It is our right to protect the sea and the land,” said Paulina Jedda Puruntatameri, a Munupi clan elder filing the complaint.

Australia’s biggest banks, ANZ, Commonwealth Bank, National Australia Bank and Westpack received the complaints, Ms Karnamadakala said, with complaints were also sent to several foreign financial institutions and export credit agencies in North America, Japan, Europe, and South Korea.

Ms Karnamadakala said the ANZ bank contributed the equal highest amount of $97 million to the $1.5 billion loan, which it has arranged with the Commonwealth Bank, and Japan’s largest bank, MUFG, each earning $3.7 million in accumulated fees.

The complaints’ recipients were asked to respond by May 16, Equity Generation Lawyers said.

Santos has not issued a statement on the action.