APW is threatening to axe 300 jobs, half its Scottish workforce, because of the slowdown in the IT, telecoms and computer markets.
Staff have been told up to 100 jobs could go at each of the company's three Scottish production centres at Hamilton, Beith and Dundee.
Union organiser Bernie Hamilton of the AEEU, said: "Management have told us privately that they will do all they can to avoid having to make any staff member redundant. We know the company will do its best to protect as many jobs as possible, but this is a very worrying time for workers."
APW personnel director Brian Graham said the planned jobs losses are a "precautionary measure" and part of a wider range of cost control measures aimed at long-term security.
"Despite this APW continues to show sales growth through these difficult times," he added.