Volkswagen South Africa said a significant number had failed to show up to work and its factories were running partial production.
Official figures suggest a quarter of all South Africans are unemployed, but some analysts put the figure at up to 40%.
The African National Congress (ANC) is still in a formal alliance with the unions and the Communist Party, but rifts have been appearing for several years.
Congress of South African Trade Unions
-Ltd..jpg?tr=w-120,h-60,c-at_max,cm-pad_resize,bg-ffffff "Thermore (Far East) Ltd.")
.jpg?tr=w-120,h-60,c-at_max,cm-pad_resize,bg-ffffff "Telangana State Industrial Infrastructure Corporation Limited (TSllC Ltd)")
.jpg?tr=w-120,h-60,c-at_max,cm-pad_resize,bg-ffffff "Taiwan Textile Federation (TTF)")
