General Motors' European employees have urged a united front against hints the car maker might close a plant in Germany or Sweden, but individual unions and officials rushed to secure local jobs, according to Reuters.

A GM Europe on Thursday said the company would probably build the next generation of Saab and Opel mid-sized cars in one instead of two plants and, although he added this wouldn't necessarily lead to the closure of a plant, the news has set alarm bells ringing, the news agency said.

"The European worker representatives won't allow themselves to be played off against each other through social dumping," top employee representative Klaus Volkert told Reuters.

He reportedly spoke after GM Europe employee representatives from GM's Opel, Vauxhall and Saab divisions in Germany, Britain, Belgium, Spain and Sweden demanded in a rare joint statement that GM guarantee to abstain from layoffs in Europe.

According to Reuters, Swedish daily newspaper Dagens Industri said the government had set up a special crisis group to make sure Trollhattan, the only Saab plant left in Sweden, would be saved.

The union representing workers in Trollhattan also reportedly said it would try to convince GM to keep building cars in the depressed western Swedish town, where unemployment of around 9% is above the national average of 5.6%.

"Now we are trying to put together a paper that we are going to give to GM. The unions and the company are trying to show that we can produce those cars here in Trollhattan," Christen Nielsen, Metall union deputy head, told Reuters. He said the unions and managers had told the Trollhaetten staff of the choice GM was planning to make.

"In a way they were shocked because it is tough information to get that perhaps in three or four years you don't have your work ... It looks like it could be a closure of the factory if we don't get it (chosen to manufacture the new car)," he reportedly added.

Reuters said that politicians in Opel's home German state of Hesse also intervened, pledging they would support the workers to push through their demands to save the Russelsheim plant.

"Together with the employees, the Hesse state government and I will personally advocate securing the (Russelsheim) location," Hesse state premier Roland Koch told the news agency.

The Europe-wide representatives reportedly said GME must devise an strategy to grab back market share through new and innovative products, thus saving jobs and preventing plant closures.

Adam Jonas, Morgan Stanley analyst in London, told Reuters the threats to the plants were a key part of the wage negotiations. "Russelsheim is not going to close ... If the plant is at 70% utilisation, that's bad, but I don't see how they could do that. It sounds like negotiating talk to me," he said.

General Motors Europe to build mid-size Opels and Saabs in one plant