More than 100 staff at two Bank of Ireland branches in Dublin are staging a one-day work stoppage in a dispute over pensions.
The staff, who are members of the Amicus trade union, are protesting at the bank's plans to reduce pension guarantees for new staff.
Amicus National Officer Jerry Shanahan has warned that if a Labour Court ruling currently awaited fails to resolve the row, the union would have no choice but to escalate its protest.
Bank of Ireland has denied that it is altering its pension arrangements for new staff to save money.
Group Head of Human Resources Michael Grealy said that the changes are essential to preserve the future pension entitlements of all staff.
He said there is a deficit in the group pension scheme of €800 million, which has to be addressed now.
He acknowledged that there was a moderate transfer of risk to the employee, but believes that the new scheme could potentially deliver the same benefits as the existing arrangements.
He also said that the new arrangements compare favourably with other institutions in the financial sector, including Allied Irish Banks, National Irish Bank and Anglo Irish Bank.
The pickets at the bank's headquarters on Baggot Street and at New Ireland Assurance on Dawson Street is not affecting branch services for customers.
Amicus represents around 500 of the banks 16,000 staff.
It has previously said it would not allow the bank to ride roughshod over their long-term pensions security.
