Stuttgart, Germany - Germany's powerful metalworkers union said Friday it would launch at the weekend its biggest campaign of strikes ever for higher pay in manufacturing industry.

At 24-hour-per-day factories, hundreds of workers will skip a shift Saturday.

The union, IG Metall, said it would then ramp up the strikes late Sunday by calling out tens of thousands of workers.

That would idle manufacturing plants of Volkswagen's premium-car division Audi, with 4,000 workers expected to stop working at just one Audi plant, in Ingolstadt.

The union is demanding a hike of 8 per cent in pay, while a representative block of employers in the automaking city of Stuttgart offered 2.1 per cent on Thursday. The union rejected this as unacceptable.

The negotiations affect 3.6-million blue-collar and clerical staff, not all of them union members, at manufacturers of metal and electrical products.

Legal restraints on striking during the current pay bargaining round expire at midnight Sunday, but the union has not yet organized a vote among its members on an all-out, open-ended strike.

IG Metall declared Friday an end to talks with employers in several German regions, saying they had been fruitless. It plans to meet November 11 with employers in the Stuttgart region where deals are usually made. (dpa)