"Management announced that there will be no more auto production after 2016," at the plant which employs 3,000 people, works committee chief Rainer Einenkel said, adding that the decision would be discussed on Monday.
A spokesman for the factory confirmed the works committee meeting on Monday but declined to comment on Einenkel's comments or provide details on the meeting's agenda.
Built in 1962, the Bochum plant manufactures the Opel Zafira model and has regularly been cited as a site to be closed as GM Europe tries to get to grips with its surplus production capacity.
In June, GM said the plant would remain in operation until the end of the Zafira's production run, at the end of 2016.
Opel, a troubled GM unit, has three other German factories, its main plant in Rüsselsheim, near Frankfurt, and one each in Kaiserslautern, western Germany, and Eisenach, central Germany.
On Wednesday, Einenkel said that Opel would return to a program of shorter work shifts in Bochum owing to weak sales of the Zafira in Europe.