Eugene Sheehy is facing into his first public test as AIB's new chief executive after the bank was forced to acknowledge new allegations of overcharging at the bank.

It emerged yesterday that AIB has been investigating new claims that AIB deliberately and repeatedly overcharged foreign exchange customers in its branches during the 1980s and the 1990s.

It is thought to be unlikely however that any new overcharging scandal that emerges from the investigations would be on the scale of the foreign exchange overcharging that became public last year.

The new allegations are believed to have emerged after a staff member took advantage of a new "speak up" facility put in place by the bank in the wake of last year's scandal.

Mr Sheehy, who took the helm at the bank in June, has until now enjoyed a honeymoon period in his role. His predecessor, Michael Buckley, steered AIB through a catalogue of scandals.

The Sunday Business Post reported yesterday that AIB compliance officers had conducted interviews with staff at AIB's headquarters in Ballsbridge, Dublin, over the past few weeks.

The staff questioned were reportedly shown pieces of paper on which names were written and they were asked if those named were responsible for the overcharging in question.

A spokeswoman for AIB confirmed yesterday that a new investigation was ongoing, but she said the process fell under a comprehensive trawl launched by the bank after the 2004 overcharging issue.

In that case, the bank was found to have levied more than €30 million in unjustified costs on customers using its foreign exchange services over an eight-year period.

The financial regulator publicly chided AIB for "deliberately hiding" the practice and the bank went about repaying the extra charges at a cost of about €50 million to its balance sheet.

The bank is thought to be keen to refute any allegations in the current instance that any individuals could be blamed over the new problems and thus scapegoated. "In all circumstances, anything that is investigated is investigated thoroughly and fairly," the spokeswoman said. The financial regulator is being updated on the matter on an ongoing basis, she added.

A spokeswoman for the financial regulator said meanwhile that the main priority in any investigation would be to identify the customers involved.

There are suggestions in this case that the process of identifying affected customers could be hampered by problems in sourcing older bank records.

Meanwhile, in an unconnected development, AIB has confirmed that Mr Sheehy will lead AIB's board to the US next month for a board meeting.

The board will take the opportunity to visit M&T Bank, in which AIB has a 22.5 per cent stake. The board meeting will be held in Buffalo in upstate New York, where M&T has its headquarters.

Despite growing speculation that the Republic's biggest bank is considering disposing of its interest in M&T, AIB claims the board members' visit to the bank is not significant in this regard.

AIB has been M&T's largest shareholder since April 2003 when it got $886 million in cash and 26.7 million M&T shares in return for selling its former subsidiary, Baltimore-based Allfirst, to the bank. AIB used the cash to buy back its own shares and continues to hold the M&T stake which is currently worth €2.3 billion.

AIB has come under some pressure from shareholders to dispose of this investment and to return the proceeds to stockholders.