Ulster Bank has walked away from pay talks with staff despite employees voting for their unions to go back to the negotiating table.
Members of the finance union IBOA voted in favour of resuming talks on a new pay and pensions arrangement after previous talks broke down.
The bank brought conciliation efforts to a halt earlier this month and said it intended to put its proposals to staff without agreement on some issues.
Larry Broderick, general secretary of IBOA - which represents almost 5,000 of Ulster Bank's 6,000 staff - said that 99% of staff in Ulster Bank Group voted to re-engage in talks.
He said Ulster Bank staff have been warned by management that a significant element of their pay - equivalent to 10% of their annual salary - is to be withheld unless they agree to sign up to a new inferior contract that will also reduce the value of their pension on retirement.
"IBOA is determined to ensure that our members are afforded every opportunity to consider the full implications of the Bank's proposals and are not rushed into hasty decisions which they will soon regret," he said.
However, Ulster Bank said it saw no point in discussing the issues again.
A spokesman for the bank said: "A period of mediation ended without agreement on a number of key issues.
"Given the position of both parties on these issues, we do not believe a resolution is possible and will not be re-entering the mediation process. We will continue to discuss Pay & Reward 2009 directly with our employees."
The pay dispute comes as it was revealed that Ulster Bank's parent, Royal Bank of Scotland, is planning to hand out bonuses of up to £5m to some of its investment banking staff. Ulster Bank has shed 1,000 jobs in Northern Ireland and the Republic since RBS was nationalised.