SYDNEY - One of Australia's "big four" banks has been hit with a record-breaking fine after admitting to engaging in widespread misconduct.

The Australian Securities and Investments Commission (ASIC) on Monday announced that the Australia and New Zealand Banking Group (ANZ) has agreed to pay A$240 million ($159.5 million) in penalties in relation to four separate investigations spanning the bank's institutional and retail divisions.

ASIC said that ANZ, Australia's fourth-largest bank by market capitalization, admitted to engaging in unconscionable conduct in dealings with the federal government by incorrectly reporting trading data relating to its management of a A$14 billion ($9.3 billion) bond deal.

Additionally, it said the bank engaged in widespread misconduct across products and services impacting nearly 65,000 customers, including failing to refund fees charged to dead customers.

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ASIC said the agreed settlement, which is subject to approval by the Federal Court, is made up of a A$125 million ($83.1 million) fine for the institutional and markets matters and a A$115 million ($76.4 million) penalty for the retail matters.

"Time and time again, ANZ betrayed the trust of Australians," ASIC Chairman Joe Longo said in a statement.

"The total penalties across these matters are the largest announced by ASIC against one entity and reflect the seriousness and number of breaches of law, the vulnerable position that ANZ put its customers in and the repeated failures to rectify crucial issues," he said.

Chairman of ANZ Paul O'Sullivan apologized for mistakes that had a "significant impact" on customers and said that several relevant executives have been held accountable.