JOHANNESBURG - Numsa is demanding a 10 percent wage increase in the auto sector.
It comes as US President Donald Trump's 25 percent tariff on cars and auto parts hits the industry hard.
Numsa says an inflation-based increase is unrealistic due to the rapidly rising cost of living.
The sector has over 300,000 workers who fall under the Motor Industries Bargaining Council.
The current wage agreement expires on 31 August.
The talks are expected to conclude within the next five to six weeks.