A strike by the National Union of Metalworkers of SA (Numsa) against the automotive industry began on Wednesday.

"It did start this morning at all seven factories, it's a total strike of all affected, between 18 000 to 19 000 [workers]," said Automobile Employers' Organisation (Ameo) spokesman Harry Gazendam.

The strike would affect the production of vehicles at Nissan, Toyota, Ford, Volkswagen, Bavarian Motor Works (BMW), General Motors and Daimler.

Each factory would lose about 400 vehicles a day in lost production due to the strike.

Gazendam said management and Numsa were trying to make arrangements for meetings to discuss a wage agreement.

The union wanted a 15 percent across the board wage increase, a 100 percent lay-off payment and the scrapping of labour brokers.

It also wanted the employer to reduce working hours to eight hours a day from Monday to Friday and allow six months of paid maternity leave.

"We will strike until the employer meets our demands. This in an indefinite strike," Numsa spokesman Castro Ngobese said on Tuesday.

Numsa could not be reached immediately for comment on Wednesday.