Staff at the Brinks Allied security firm have voted in favour of taking formal strike action in their dispute with management over new security measures.
Speaking on RTE radio, SIPTU spokesman Kevin McMahon said 60 workers voted for strike action and nine against.
He said the union will be looking for sanctions, and if these are approved, strike notice will be served on Brinks to take effect from next Thursday. He said the action would close down all operations at Brinks.
The two week old dispute has already led to the closure of about 240 cash machines in the east of the country.
Talks at the Labour Relations Commission, which ended on Monday, failed to resolve the issue.
Strike notice is expected to be served tomorrow which would allow for all-out action the following Thursday, August 19.