600 staff at Bank of Scotland Ireland have voted overwhelmingly to take industrial action.
The dispute is over the establishment of a separate company to handle the winding down of the bank's operations in Ireland.
94% of staff voted in favour, with a turnout of over 80%.
Their union, UNITE, said staff have not been given sufficiently clear assurances about what terms and conditions they will have in the new company.
The union will serve notice of industrial action tomorrow, and is expected to hold a 'day of inaction' next Wednesday, when staff will refuse to use phones or computers.
The bank has a €32bn loan book to be run down in Ireland.
