Pan-European unions have cited recent comments by Fiat CEO Sergio Marchionne concerning capacity reduction as a "green light" for other automakers to wield the axe while rumours build of two Opel/Vauxhall plant closures.

Marchionne mooted the potential shutting of two Italian plants as Fiat struggles in Europe - comments unions fear could lead to Opel imminently announcing similar plans.

Opel is declining to comment on the intense speculation, but events could now move quickly as a supervisory board meeting is scheduled for next week.

Intense speculation is focusing on Opel/Vauxhall's Bochum site in Germany, Ellesmere Port in the UK or both which could be under threat, although union sources insist to just-auto that parent General Motors cannot act in any case until 2014.

Opel has suffered chronic losses of late, the most recent being a vast US$700m negative result for 2011 and has previously said it would unveil a restructuring plan for Europe - largely believed to involve the closure of two sites to address the issue of massive over-capacity against a stagnant and falling market.

"There is no comment - we have seen these reports but we do not comment on speculation," a GM Europe spokesman told just-auto from Germany."

Despite GM's reluctance to talk about the situation, the rumours have spooked unions in both Germany and the UK, already nervous about the pending alliance between the Detroit automaker and PSA Peugeot Citroen, as well as any impact resulting synergies could have for jobs.

"If there is a need to restructure production, it is a situation that threatens the existence of the industry itself," European Metalworkers Federation (EMF) automotive head, Wolf Jacklein told just-auto from Brussels. "Not just cars, but productive industry itself.

"There is a European context where [Fiat CEO, Sergio] Marchionne has given a sort of green reduce capacity. It is financial strategy of the short term - the result is there will be de-industrialisation. There is no industrial strategy beyond this strategy to reduce capacity."

The EMF automotive head also warned such talk of over-capacity could be a bargaining tool by manufacturers to wring concessions from employees as they made strenuous efforts to cut costs.

"These rumours are launched with the objective - first of all to launch a debate then to put pressure on workers to get concessions," he said. "For the business concretely, there is neither the possibility now to reduce capacity because we have an agreement until 2014."

The EMF umbrella union last week maintained Opel and GM had rejected talks and were trying to "play one site against another and put brutal pressure on worker bodies."