The government's financial intelligence agency has examined the ATM systems of Commonwealth Bank's rivals and is confident they have not had the same problems in reporting large cash transactions to authorities.

Austrac, which is alleging systemic breaches of anti-money laundering laws by CBA, on Friday also said it did not "take lightly" its unprecedented legal action against the country's biggest bank.

"It's not something we take lightly, obviously," acting Austrac chief executive Peter Clark said before a Senate estimates hearing.

"We give very careful consideration to what measures we seek to apply in terms of addressing non-compliance, particularly if it's of a serious nature. So, a lot of careful consideration was given before filing civil penalty proceedings in this case."