The six Tiwi Islanders and a member of Larrakia Nation lodged grievances with ANZ, Commonwealth Bank, NAB and Westpac and eight international banks over the loans, an activist group supporting them announced on Tuesday.
Other banks receiving the complaints are ING, DNB Bank, Citigroup, Royal Bank of Canada, DBS Bank, MUFG, SMBC and Mizuho.
Equity Generation Lawyers, a law firm devoted to climate change, filed the complaints with the banks on behalf the traditional owners, requesting a response by May 16.
The complaint filed with ANZ relies on the bank's grievance framework it introduced in November 2021 to respond to human rights complaints.
The mechanism was set up after ANZ's Cambodian arm approved a loan to a sugar company that forcibly seized land from 681 families in collusion with state authorities.
"By entering into loans to finance the Barossa project, the banks are contributing to the immense impacts of this project on our clients' ancient and continuing spiritual and traditional connections to their ancestral lands and waters," said Vidhya Karnamadakala, an associate at Equity Generation Lawyers.
"Banks appear to be breaching their own human rights policies. Banks cannot fund the Barossa gas project without the consent of our clients and the Tiwi communities."
The 39-page complaint filed with ANZ asks the bank to publicly accept that it has contributed to "adverse human rights impacts of the Impacted Tiwi Communities."
It asks for a public apology as well as the bank paying profits from the loan to the affected Tiwi communities as compensation.
"ANZ will consider the matter in line with the processes under our Human Rights Grievance Mechanism," an ANZ spokesperson told AAP in an email.
Santos says it has consulted with the traditional owners since 2016 on the Barossa gas project, which it calls an important project for the nation that will enhance jobs and exports.
The project, which involves drilling 140km north of the Tiwi Islands, is about half completed and set to deliver first gas in 2025.
