Porsche says it will have to cut workers’ hours owing to a slump in sales. The sportscar maker foresees 18 days of shorter working hours by the end of the year at its main plant in Zuffenhausen, southwestern Germany, a statement said.

Personnel director Thomas Edig said the company had managed to avoid such measures so far through the use of flexible schedules agreed to by workers. But those “have reached their limits”.

Porsche sales have fallen over the past few months and key export markets are not expected to rebound strongly during the next 12 months, the company said. Results for the 2008-2009 fiscal year will be announced during the Frankfurt motor show.

In late July, Porsche forecast a pre-tax loss of EUR5bn (US$7.15bn) following the collapse of its bid to take over Volkswagen. Now it is planned to integrate Porsche into VW as a 10th brand.

Porsche’s statement added that it still expects to report a profit margin of at least 10% for the year.