The motor parts company is based in Campsie, County Londonderry
There are fears that a County Londonderry motor parts company is to close its Campsie plant with the loss of more than 100 jobs.
An extraordinary general meeting of Calcast's board of directors is planned for next week.
Philip Oakes, from the Unite trade union, said no official decision had been made.
A Calcast spokesman said they were contacting employees to inform them about the factory's future.
Foyle MP Mark Durkan said he feared the worst.
"Unfortunately we know from past experience when you're told that a meeting is going to take place, often in effect the decision has already been taken," he said.
"What we need to do is see is there any way of influencing the company to take a different decision.
"Can they create different conditions for this plant, maybe by placing work for other parts for different vehicles into this plant?"