FRANKFURT (Reuters) -Volkswagen said it was hit by a major IT outage on Wednesday, causing production at the carmaker's namesake brand in Germany to come to a halt.

Volkswagen, Europe's top carmaker, said the whole group, which includes the Porsche AG and Audi brands, was affected.

A spokesperson for Audi confirmed that production at the division had been affected as well, adding the extent of the impact was being analysed.

Porsche AG had no immediate comment.

The carmaker is already grappling with lower production at its all-electric Zwickau plant, where muted demand for battery-powered vehicles may change a long-standing three-shift system.

Volkswagen said there had been an unspecified "IT malfunction of network components" at its site in Wolfsburg, Germany, its global headquarters.

The outage also affected German sites in Emden, Osnabrueck, Hanover, Dresden and Zwickau, and component factories in Braunschweig, Kassel, Chemnitz and Salzgitter, the company said.

"The fault has been present since 12:30 p.m. (CET) and is currently being analysed. There are implications for vehicle-producing plants," the group said.

"According to current analyses, an external attack is unlikely to be the cause of the system malfunction," Volkswagen said, adding that efforts to fix the problem were of the highest priority and well under way.

(Reporting by Christoph Steitz and Ralf Banser; Writing by Maria Martinez; Editing by David Holmes, Grant McCool, William Maclean and Richard Chang)