A government minister has again dismissed the calls.

Australia’s labor party has renewed its calls for a wide-reaching public inquiry known as a royal commission into the country’s banking sector after reports that criminal groups have used large lenders to launder drug money. 

Up to A$5 million ($4 million) a day is being washed through Australia’s big four banks – National Australia Bank, Commonwealth Bank, ANZ and Westpac – according to local media reports. 

In addition to Australia’s largest lenders, crime groups have also exploited mid-tier institutions like the Bank of Queensland and Bendigo Bank, reports say. 

Labor frontbencher Anthony Albanese has said the revelations are “another argument” for a royal commission into the sector. 

“We need a banking royal commission, and I don’t know why the government is resisting this,” he said. “It will happen, let’s get on with it.”

But government minister Christopher Pyne has again dismissed the calls, claiming it would take “years and years to report and to do anything”.

The money laundering saga has already caused shockwaves through Australia's financial system. Commonwealth Bank of Australia (CBA) was hit earlier in September with a class-action lawsuit over a money laundering scandal that has already shaved billions off its market value and rattled Australia’s financial sector. Meanwhile, the bank said it will not file its defence against separate allegations from a financial intelligence agency accusing it of failing to report hundreds of suspicious transactions until mid December. CBA is also under investigation by Australia’s banking and corporate watchdogs over the suspicious transactions.