Major Australian banks have been under pressure to rule out funding Adani's controversial Carmichael mine, but the former CEO of Australia's second-biggest miner says the Indian giant does not need their money anyway.

Speaking at a business lunch in Brisbane, former Rio Tinto chief executive Sam Walsh described the idea the company needed australian banks to get the Galilee Basin project off the ground as a "furphy".

Former Rio Tinto chief Sam Walsh has been enmeshed in Rio's bribery scandal in West Africa. Credit:Robert Shakespeare

"I don't believe Adani actually needs any finance from any Australian bank," he said, adding finance would likely come from overseas.

Resources Minister and apparently soon-to-be former Westpac customer Matt Canavan branded the company "wimps" after it ruled out funding the mine after intense lobbying from Adani opponents, who also cast doubt on its financial viability.