Volkswagen, General Motors Co. and BMW are among carmakers whose production has been hit by a strike in South Africa today as 30,000 metalworkers take action to demand higher pay.

“The strike started today,” Castro Ngobese, a spokesman for the National Union of Metalworkers of South Africa, said by phone. “There are no negotiations, since they broke down. We are waiting for employers to submit a revised offer.”

The union is demanding a 14 percent annual wage increase alongside improved medical benefits and shift flexibility, according to NUMSA National Treasurer Mphumzi Maqungo.

South Africa has been plagued by labor strikes that have spread from the mining industry to other parts of the economy. The automobile industry accounts for almost 7 percent of the country’s gross domestic product, according to the Department of Trade & Industry.

The strike, which has also affected Toyota, Daimler, Nissan and Ford, may cost the industry as much as 700 million rand ($69.1 million) a day by reducing vehicle output by 3,000 vehicles, the National Association of Automobile Manufacturers of South Africa said on Aug. 16.

“Workers are on strike since this morning,” Lunga Ntsendwana, product communications manager for GM, said by phone. “They have gathered outside the plants. About 80 percent of the workers are on strike.” GM’s South African unit has two plants in Port Elizabeth. It makes Chevrolet cars and Isuzu trucks in Africa’s biggest economy.

Dudu Mwelase, a spokesman for Nissan’s South African unit, said in a phone interview that daily output of about 245 units is disrupted due to the strike.