German industrial companies face all-day walkouts by workers next week that could hamper the production of cars, car parts and machinery as 16 hours of last-ditch regional talks between union IG Metall and employers failed to yield a deal.

Nearly a million workers have already taken part in short walkouts across the country this month to support IG Metall's demands for higher pay and the right to shortened working hours, but 24-hour strikes may pose a serious risk to industrial output in Europe's biggest economy.

Employers in the southwestern state of Baden-Wuerttemberg, home to companies such as Mercedes-Benz maker Daimler and sports car firm Porsche, said on Saturday the union had made new demands in the fifth round of talks that were not negotiable.

IG Metall was now demanding an 8 percent pay rise for 3.9 million metals and engineering workers across Germany for 27 months, regional employers' association Suedwestmetall said.

The union is also asking for workers to receive the right to reduce their weekly hours to 28 from 35 to care for children, elderly or sick relatives, and return to full-time employment after two years.

Employers have offered a 6.8 percent increase but have rejected the demand for shorter hours unless they can also increase workers' hours when necessary.

"In the end, the union was not even willing to consider the costs (from workers shortening their hours) in the overall demand," Stefan Wolf of Suedwestmetall said.