The Greens are targeting the big four banks with a proposed 0.2 per cent levy on bank assets in excess of $100 billion, accusing them of "getting a leg-up that no other industry has".
Greens MP Adam Bandt said the levy, which could raise more than $8 billion over four years, would ensure that the "big four banks paid a fair contribution for the public support they receive".
"[They] are making record profits, of about $24 billion in the past year. These record profits off the back of consumers are underpinned by an implicit 'too big to fail' guarantee from the government," a party statement said. "If the banks went to the wall the taxpayer would bail them out." It said they were taking all the profits while taxpayers took all the risk.
Mr Bandt said such a levy would bring Australia into line with other parts of the world.
"Our banks are in rude financial health and are the world's most profitable banks. The reason why is that they have the government and the public standing behind them giving them a leg up that no other industry has," he said.
The Greens have previously been strong advocates of the mining tax.