General Motors’ Adam Opel will reduce planned output of Corsa cars at its eastern Germany plant in Eisenach later this year amid slack demand for the model.

Reuters said this was the second time this month that Opel has scaled back Corsa production at Eisenach, which makes cars primarily for the sluggish German market.

An Opel spokesman reportedly described as “realistic” a story in the Frankfurter Allgemeine Zeitung newspaper that the 1,800 staff at Eisenach in eastern Germany would work shorter hours for between 6 and 15 days as a result of the measures.

Opel had said early this month that it would suspend production of the compact Corsa in Eisenach for 11 days in October amid sluggish demand.

Spokesman Frank Klaas told Reuters the Corsa was well received by customers but the problem was a general slowdown in the German car market, Europe’s biggest.

New car registrations in August hit an eight-year low for that month, and the VDA industry association is counting on a late-year rally just to match 2003 sales of 3.24 million, the news agency noted.

“The Corsa is still number two in the overall compact car segment and we are still building more cars than two years ago, but we had to row back a bit because of the market,” Klaas told Reuters.

Corsa production at Eisenach is now set to hit 140,000 units this year, more than the 127,100 built in 2003 but fewer than the 158,000 Opel had originally envisioned, the report said. Productivity gains have let it increase output while still limiting working time.

The Eisenach plant makes Corsas and Astras. The Opel plant in Zaragoza, Spain, also makes Corsas and Corsa vans, Reuters noted.

The news agency said reduced Corsa output comes against the backdrop of tense wage negotiations at Opel, where GM’s loss-making European arm wants to freeze workers’ pay to the end of 2009 and extend the work week without extra compensation.