Investors are bracing for a share market reaction after the Commonwealth Bank (CBA) admitted it breached Australia's money laundering and counter-terrorism regulations and indicated more charges could be brought against it.

Months after Australia's money laundering regulator, AUSTRAC, launched legal action against CBA, Australia's biggest bank has admitted it breached statutory disclosure laws more than 53,000 times.

AUSTRAC has indicated it proposes to file an amended statement of claim containing additional alleged contraventions, CBA said in a statement to the ASX.

CBA said it would defend more than 100 more serious allegations regarding its alleged failure to disclose suspicious transactions.

The bank potentially faces multi-million-dollar fines. The matter is next due in court on March 16 next year.

AUSTRAC accused the CBA of failing to flag more than 53,000 transactions which exceeded a $10,000 limit and passed through its smart ATMs between November 2012 and September 2015.

In October, law firm Maurice Blackburn and litigation funder IMF Bentham filed a statement of claim in the Federal Court in Melbourne saying the CBA board knew of the potential breaches in the second half of 2015 and failed to inform shareholders for two years.

The class action is on behalf of all shareholders who bought CBA shares between July 2015 and August 3, 2017.

Top executives at the bank, including outgoing chief executive Ian Narev and current board chairwoman Catherine Livingstone, have been singled out in the class action as knowing about the compliance issues but failing to act.