The finance union, IBOA, says Ulster Bank's announcement that it intends to make significant changes to the defined benefit pension scheme for staff and to freeze pay for 2009 is 'totally unacceptable'.
The IBOA's general secretary Larry Broderick said the bank's proposals have not been discussed nor agreed with the union.
'We consider that our members in Ulster Bank are once again being scapegoated for the profligate lending policies of senior management in both Ulster Bank, and its parent company Royal Bank of Scotland.
Mr Broderick said that despite huge sacrifices by Ulster Bank staff, including a major restructuring programme involving 750 job losses already under way and another 250 redundancies being sought, staff are being asked to bear the brunt of this mismanagement.
The IBOA said it will now consult with its Ulster Bank members to determine a practical response to the RBS proposals.