Opel's IG Metall union has expressed its anger at the "hard line" from management surrounding the possible ending of Bochum production at the beginning of January, 2015.

The powerful labour body in tandem with Opel's Group Works Council, labelled any decision by the General Motors-owned automaker to potentially stop manufacturing at the plant, employing some 3,000 staff, in 2015, as "unacceptable."

Union irritation has been stoked by the emergence of a letter sent yesterday (22 January) by GM vice-chairman, Steve Girsky, to Opel staff in which he raised the chance Bochum could shut on 1 January, 2015 instead of previous indications the site could continue until the end of 2016.

"We were surprised he [Girsky] said his message in this time and in this confrontation," a North-Rhein Westphalia - where Bochum is based - IG Metall spokesman told just-auto from Germany. "We think there is more time to have a good discussion but not a message that makes people very angry.

"It is a hard line and it is not necessary to have this hard hard line. We say we need new contracts from GM for all the workers and for all the factories - we don't need that GM says there will [be] only close [ures of] factories."

Ending vehicle production at Bochum is believed to be the first time such a situation has occurred in Germany since the end of World War II and comes at a time when several European manufacturers are looking at drastic plant closures and staffing reductions.

Girsky's letter appears designed to kick-start talks on pay and conditions at Opel's German plants, with a GM European spokesman conceding it was "understandable" the vice-chairman's comments had provoked attention.

"The original plan said the plant [Bochum] was safe until the end of 2014 - we said OK if we you start negotiations now we can keep the plan running until the end of 2016," a GM Europe spokesman told just-auto from Germany.

"That was the original starting point. He [Girsky] said of course if you can't start talks, that is a status where we have to go back to. It was perceived from the unions in Bochum - they were not happy with that. It was an action by Girsky saying we have to start negotiations now and we have to be more cost efficient.

"He did not give any specific indication of what he was making reference to."

Talks are complicated by regional wage bargaining across North-Rhein Westphalia for example, that set a 4.3% pay rise, but this could be offset by compromises in other areas of salary and productivity.

"The 4.3% is what the workers expect for the region [al] metal industry," said the GM Europe spokesman. "So far, we don't pay it. We wait until negotiations are finished. We can of course pay this 4.3% and save in another area. That is something we have to sort out with the local unions.

"There are many ways to get a deal. Of course we have to stick to that local wage increase."