Staff at the four Marks and Spencer stores earmarked for closure have voted overwhelmingly in favour of industrial action.
The retailer is planning to close its operations in Dun Laoghaire, Tallaght, Mullingar and Naas, with the loss of 180 jobs.
Workers, represented by Mandate, have voted by a margin of 88% in favour of action to oppose the closures.
The trade union says pickets will be placed on the four stores on or after September 10, and it is warning the action could spread to other stores.
"We're aware that there are other jobs in the stores in the Marks and Spencer network," said John Douglas, General Secretary at Mandate.
"These long-serving staff from Marks and Spencer should be allowed to transfer into those stores and take up employment."
The stores stopped trading on Saturday last, August 17, but the workers are still employed in clearing the locations.