Traditional owners have lodged human rights complaints against 12 banks over their involvement in Santos' $4.7 billion Barossa gas project.

The grievances are the latest complication for the gas project after the Federal Court last year ruled Santos' approval for it was invalid.

The approval was overturned due to a lack of consultation from Santos with traditional owners.

The Barossa project, north of Darwin, is currently paused and faces increased costs from changes to the federal government's safeguard mechanism.

The human rights grievances have been lodged by six people from the Munupi, Malawu and Jikilaruwu clans on the Tiwi Islands, and one from Larrakia country in Darwin, assisted by Equity Generation Lawyers.

The complaints were made against ANZ, Commonwealth Bank, Westpac, and NAB, for their involvement in a $1.5 billion loan.

Eight international banks and three international export credit agencies have also received complaints.

"Most of these banks have human rights policies, and they have what's called a human rights grievance process," Equity Generation Lawyers associate Vidhya Karnamadakala said.

"[It] invites impacted communities to write to the banks, and to alert them as to the human rights impacts of certain projects that they might be financing."

Ms Karnamadakala said her clients had used the grievance process to tell "the banks that the … project is having a serious impact on their economic, social and cultural rights".