The Irish Bank Officials' Association has been "inundated" with enquiries from IFSC workers in particular after figures for unpaid overtime were published recently by the Central Statistics Office, said Larry Broderick, the union's general secretary.

"We believe this abuse of staff is most widespread in non-union areas of the business and in particular among younger employees in the financial services sector, " he said.

"This in effect amounts to profitable institutions stealing from their employees and under no circumstances will this be allowed."

The overtime row comes at a delicate stage in negotiations for a new national pay deal and the IBOA has already broken ranks with other unions by demanding a 10% pay hike for its members.

"At a time when the talks on a new national agreement are bogged down on the issue of displacement of workers and mis-treatment of foreign nationals working here, it is outrageous that companies in the financial sector can treat staff in this manner, " Broderick said.

"IBOA will be raising this issue with ICTU as part of the negotiations on a new agreement."