More than 1500 of the late reports to authorities related to transactions connected to suspected money laundering syndicates,it said.

Six of these late reports related to five customers"who had been assessed by CommBank as posing a potential risk of terrorism or terrorism financing",Austrac said in its statement of claim.

CBA acknowledged the civil proceedings had been brought and said it would have more to say on the specific claims"in due course". The bank potentially faces a huge fine as each contravention carries a $18 million penalty.

CBA said it took its regulatory obligations"extremely seriously". It had been in talks with Austrac for an"extended period"and had fully co-operated with the agency's requests.

The effect of CommBank's conduct in this matter has exposed the Australian community to serious and ongoing financial crime.

Austrac

"On an annual basis,we report over 4 million transactions to Austrac in an effort to identify and combat any suspicious activity as quickly and efficiently as we can,"the bank said.

The case comes after a series of scandals have affected the banking industry in recent years,and the Finance Sector Union claimed it highlighted the need for a royal commission into the sector.

Austrac refers to at least four different money-laundering syndicates that are alleged to have used CBA's ATMs,but alleges the bank failed to report suspicious activity as required.

Austrac alleges much of the suspected money laundering that occurred through CBA's ATMs was done with deposits of just under $10,000,and CBA identified the suspicious patterns of activity but repeatedly failed to report them to authorities.

CBA is also required to monitor customers with a view to spotting money laundering or terrorism-financing risks,but the bank failed to do this as well,Austrac alleges.

Even when suspected money laundering was brought to the bank's attention,Austrac alleges CBA did not monitor customers at risk of money laundering. Some customers were allowed to make suspicious transactions after the bank had given 30 days'notice that it intended to terminate their accounts,it alleges.

The bank's failure to report $10,000 deposits on time,pass on its suspicions,and monitor suspicious customers had deprived law enforcement agencies of intelligence and evidence,and allowed further money laundering and lost proceeds of crime,it says.

Austrac's acting head,Peter Clark,said the court action followed an investigation into CBA's compliance,particularly relating to its use of IDMs.

"By failing to have sound AML/CTF[anti-money-laundering/counter-terrorism financing] systems and controls in place,businesses are at risk of being misused for criminal purposes,"Mr Clark said.

"Austrac's goal is to have a financial sector that is vigilant and capable of responding,including through innovation,to threats of criminal exploitation."

CBA said it had invested more than $230 million to comply with anti-money-laundering rules,and all of its staff had to complete training on the act.

The action against CBA comes after gaming giantTabcorp paid $45 million to settle a money-laundering case with Austrac in February.