Workers at the Element Six plant in Shannon, Co Clare are to hold a ballot for official industrial action over the next few days.
The decision was made after a meeting of union and non-union workers this morning to discuss the workers' response to the company's plan to save 160 jobs.
The company has said the survival plan would involve a comprehensive change in work practices and increased productivity.
SIPTU says its members are angry that a better redundancy package has not been offered. It says it does not believe that the jobs saved are for the long term.