SIPTU workers at Teva Pharmaceuticals in Waterford city have voted in favour of industrial action at the plant in a disagreement over redundancy terms.
Last September the company closed the tablet making facility which led to 300 redundancies at the plant.
SIPTU, which represents over 400 workers at the plant, has said that one of the reasons for the strike action is the unfair selection for redundancy.
Teva is one of the largest generic pharmaceutical companies in the world.
The company, which has its headquarters in Israel, intends to maintain an inhaler making facility in Waterford employing around 400 people.
No date has yet been set for the industrial action.