FRANKFURT (Reuters) - Volkswagen <VOWG_p.DE> plans to reduce working hours at a German plant making Passat cars because of problems with supplies from its in-house seat manufacturer Sitech.

A spokesman for the plant in Emden, in Volkswagen's home state of Lower Saxony, said about a third of the factory's 9,000 workers would be affected, initially for a period from Aug. 18 to 24.

The factory makes 1,250 Passat cars a day on average, including the CC coupe version.

(Reporting by Georgina Prodhan; Editing by Greg Mahlich and David Evans)