The Irish Bank Officials' Association (IBOA) will ask its members if they reject the plan to shut the main pension scheme to new recruits.

None of the workers being balloted is directly affected (the move will apply only to people hired after 1 October) but their support will be critical to the IBOA's opposition to what it claims would create a two-tier workforce with very different pension benefits.

The row has shot to prominence because it is holding up final agreement on a new national pay deal, as unions press for measures to make it harder to exclude new recruits from the pension ebitlements enjoyed by existing workers.

IBOA general secretary Larry Broderick has described the bank's decision as "morally reprehensible" and "an example of the worst type of corporate greed".

Bank of Ireland chief executive Brian Goggin rejected that as "ill-judged and disingenous" in unveiling record 1.6bn profits last week. "This is not a short-term, cost-expedient measure. We are being extremely progressive and extremely responsible."

Meanwhile, the bank is set to finalise an outsourcing contract that will result in hundreds of staff members being transferred to the British building services firm.