SIPTU has declared that it wants unions at Diageo to adopt a united stance to oppose any compulsory redundancies at the drinks company.
The company plans to close its breweries in Dundalk and Kilkenny and transfer its Guinness brewery from St James Gate in Dublin to a greenfield site on the west of the city.
The plan could mean up to 250 job cuts.
SIPTU shop stewards have said that they will oppose any compulsory redundancies or reduction in conditions during the restructuring.
The union said its aim was to protect as many jobs as possible and maintain existing terms and conditions.