Cosatu supporters protesting against the e-tolling system and labour brokers started marching from Beyers Naude Square in Johannesburg around 10am on Wednesday.
Marshals were controlling the crowd, which had almost filled the square, while more protesters joined the throngs by the busload and on foot.
Protesters were converging on the square from all directions.
Earlier Aggie Semenya, who works for Joburg Water, said electronic tolling would eat into her already tight finances.
“I am striking to stop toll roads because I spend a lot already on transport and this is going to get worse. I travel from Soweto to Sandton every day.”
Vivian Buso said she was joining the nationwide strike because she wanted a full time job.
Fellow protester Justice Moloto said: “I want a full time job, that's is why I am supporting this protest. For 13 years I have worked for the post office, but because I was employed by a labour broker I stayed temporary, earning R2000 a month. I should be permanent, earning R8000 a month. Labour brokers must go.”
Obed Aphanye said he was worried about how e-tolling would affect his livelihood.
“I am here over the (toll) gates. As a driver I can see what these tolls are going to do to businesses and ordinary people. They cannot be allowed.” - Sapa