AIB's response to overcharging customers indicates there is "no change in the culture" at the bank, the Consumers' Association of Ireland (CAI) has claimed.
The consumer watchdog said it has warned for years of the lack of policing at the interface between Irish consumers and banks.
Consumers' Association of Ireland
"The response from AIB indicates that there appears to be no change in its culture and an enormous deficit in its understanding of the consumer position", the CAI said.
"The fact that Irish legislation has been hugely deficient in providing protection for consumers, and that consequently the finding that AIB, largely, did not break the law, should provide no comfort to the board of AIB."
The small business's group ISME said the report into AIB overcharging outlines the urgent need for a review of the banking sector.
Mr Robert Berney, ISME chairman, said: "Today's report indicates that there is a malaise within AIB with regard to the treatment of their customers that the Association feels extends to the whole banking sector".
"What is particularly galling is the fact that AIB failed to notify the regulator (Irish Financial Services Regulatory Authority) as required by law of the extent of their overcharging of customers.
He said it was ironic that the problems only came to light following an anonymous caller. This, he said, confirmed the "regulatory process in place to adequately monitor and control the sector has patently failed".
Opposition parties responded to the IFSRA report published this morning by calling for a change in the culture of banking in the State.
Mr Richard Bruton, the Fine Gael finance spokesman, said the reaction of AIB to the problems "smacks of complacency" and fails to understand the level of public frustration.
He also highlights a difference of language between the IFSRA report and the bank's statement.
"While IFSRA quite bluntly presents 'failures' on the part of AIB, the AIB statement talks of errors and oversights and presents itself as going way beyond its obligations in paying back to customers charges".
Mr Bruton added that because no penalty has to be paid by the bank except returning what was wrongly collected the public will be left with a sense of grievance.
The Labour Party finance spokeswoman, Ms Joan Burton, said only when the question of why the overcharging went on for so long were answered would it be possible to start restoring confidence in AIB and the Irish banking sector.
Ms Burton said the IFSRA and AIB reports on are a "shocking indictment of banking malpractice". However, she welcomed the bank's decision to refund over-charged customers.