Contrary to Labor’s claim that the alleged manipulation of the bank bill swap rate has a huge impact on every home loan mortgage, the government stressed that it is the cash rate, not the BSBW rigging, that has a great influence on pricing mortgages.

“It is wrong to allege that the home loan contract is linked to the bank bill swap rate,” said the head of the government’s financial system inquiry, David Murray. He added that politicians have “been strident in demands that banks should respond to the RBA cash rate” by passing through its reductions to their own customers.

Likewise, Greg Medcraft, the chairman of the Australian Securities and Investments Commission, said that homeowners had not been directly affected by the regulator’s claims that three of the major banks rigged the key benchmark interest rate on multiple occasions between 2010 and 2012.

But Opposition leader Bill Shorten described the rate-rigging purportedly done by ANZ Banking Group, Westpac Banking Corp, and National Australia Bank as “cancer eating away at the trust and confidence Australians have in their banks.”

“Every mortgage, every home loan has potentially been rigged by Westpac and that is what the charges being made by the banking regulator is,” added Labor senator Sam Dastyari. “This is potentially the largest financial crime of its type ever in Australian history.”

The cases carry a fine of $1 million for each transgression, which could mean a possible total fine of more than $50 million for NAB, $16 million for Westpac, and $44 million for ANZ.