Several thousand protestors marched through Johannesburg Wednesday to demonstrate against a proposed minimum wage, a new test for President Cyril Ramaphosa who took office in February.
South Africa, which is suffering record unemployment, is due to introduce the 20 rand ($1.60) hourly minimum wage, but it has been widely criticised as too low.
"It is a disgrace," said Martin Kgaladi, a car industry worker wearing a T-shirt denouncing the pay level as "a salary of slaves".
He accused Ramaphosa, a former trade union leader who supports the minimum wage, of being "captured by the capitalists and oppressing the workers he once defended."
Ramaphosa has vowed to boost economic growth and tackle unemployment by attracting foreign investment and cracking down on government corruption.
He took over from scandal-tainted Jacob Zuma after nine years of weak growth, ballooning national debt and falling investor confidence.
SAFTU, the second biggest trade union, also held protests in Cape Town, Durban and Port Elizabeth, but the strike was not backed by COSATU, the biggest union group, which is a government ally.
Employment has hit a high of 28 percent in South Africa, with the youth unemployment levels often peaking at over 50 percent in some areas.
Last week, Ramaphosa left a summit in London early to hold talks over violent riots against alleged government corruption and poor public services.