Traditional owners have taken aim at Westpac for dismissing concerns over its involvement in loans to Santos contributing to the Barossa gas project.
Six Tiwi Islanders and a member of Larrakia Nation last month lodged grievances with Australia's big four banks and eight international banks over the $US1 billion ($A1.5 billion) loans.
Prepared by Equity Generation Lawyers, the 39-page complaint sent to Westpac alleged it was contributing to adverse human rights impacts on Tiwi and Larrakia traditional owners.
But in a letter sent to the law firm in response, Westpac disagreed with the assessment.
"As a participant in those syndicated loans, it is not correct to characterise Westpac as having contributed to the alleged potential or actual human rights harms," chief sustainability officer Siobhan Toohill wrote.
"This is not a correct description under any applicable domestic laws, prevailing human rights standards or Westpac's own policies."
The complainants had invited Westpac representatives to sit down with Tiwi elders on country to explain its position.
Ms Toohill said Westpac would instead engage directly with Santos on the allegations.
"We take the claimants' concerns seriously and would like to assure the claimants we will engage with Santos in good faith in relation to those concerns," she wrote.
Munupi elder Dennis Murphy Tipakalippa said Westpac had ignored the wishes of traditional owners.
"We've asked them not to support Santos for this Barossa project," he said in a statement released by Equity Generation Lawyers and activist group Market Forces.
"It's hurting us and it will hurt our environment now and over the long-term future."
Market Forces acting chief executive Will Van de Pol said Westpac would face backlash for its decision.
"Westpac's disrespectful dismissal of these traditional owners' human rights concerns is yet another example of failing to live up to its claims and commitments on social issues," he said.
"Customers and shareholders will not stand for Westpac continuing to prioritise its relationships with destructive companies like Santos over communities."
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.
