General Motors Europe has declined to comment on a “speculative” German newspaper report that it will build the next-generation Astra at four plants in Europe, including its German factory in Bochum.

The newspaper was Auto Zeitung, which cited Opel sources, according to Reuters.

A GM Europe spokesman in Zurich called the report “speculative” and declined further comment. A spokesman for GM’s German brand Opel also declined comment.

The paper reportedly said an announcement was due on Tuesday, 17 April but did not name the other three plants that will get work building the new generation car on the new Delta platform. The Astra is GM’s best-selling car in Europe with nearly half a million units sold last year.

GM makes the current Astra in Antwerp, Belgium, Bochum, Germany and in Ellesmere Port, Britain. Its Gliwice plant in Poland and the Trollhattan factory in Sweden also want the work, Reuters noted.

The news agency added that labour representatives said this month GM’s European workforce has already offered to cut costs by about $US393million (EUR290m) to improve competitiveness in the hope of preventing the closure of a another European plant.

GM Europe’s top labour leader, Klaus Franz, told Reuters there had been no decision yet on production sites for the next Astra, which is due for launch in 2010.