The Irish Bank Officials Association (IBOA) warned AIB against scapegoating rank-and-file staff with the regard to the overcharging controversy.

The IBOA's general secretary, Mr Larry Broderick, said that it was unacceptable that senior figures at AIB should attempt to blame junior employees ahead of a thorough investigation into the affair.

He called for an independent inquiry to be conducted and for its findings to be made public.

It seemed that the lessons of the John Rusnak debacle, in which the trader racked up $691 million (€580 million) losses at AIB's US subsidiary Allfirst, had not been taken to heart, said Mr Broderick. "After Rusnak, IBOA was assured that proper controls and procedures were put in place in AIB and I find it extraordinary that this development has taken place unknown to senior management in the bank."

He also urged the establishment of a national forum to examine ethics in the banking industry, comprising the Government and the major sector players.

"Given the recent spate of scandals in Irish banking, it is incumbent on all interested parties in Irish banking to put in place clear, ethical standards to reassure customers and bring confidence back into Irish banking," he said.

The Irish Exporters Association has advised members to review foreign exchange transactions with AIB from May 1996 to April 2004and to seek follow-up meetings with the bank to determine whether any compensation is due.

The affair will fuel suspicions that AIB was reaping record profits not because it was a dynamic institution but because it was beholden to a "greed is good philosophy", according to ISME, the small business lobby.

"For many years now, the Irish banks have consistently been the most profitable or amongst the most profitable banks within the EU commensurate with their size," ISME chief executive Mr Mark Fielding said. "We could be proud of that performance if it was not for the lingering suspicion and perception that it was a product of greed rather than deed."

Fine Gael called for the Government to clarify if AIB could be prosecuted for its failure to detect overcharging. Finance spokesman Mr Richard Bruton said there was confusion over whether the Irish Financial Services Regulatory Authority (IFSRA) had inherited the Director of Consumer Affair's powers to take court action against errant institutions when it inherited the director's responsibilities in the financial services sector.

Labour leader Mr Pat Rabbitte called for the introduction of legislation protecting "whistleblowers" in the wake of the scandal, which came to light when IFSRA received an anonymous tip-off.