Cosatu and the SACP have called on workers, ANC supporters, and even Cabinet members, to join their march against state capture and President Jacob Zuma.
Labour federation the Congress of South African Trade Unions (Cosatu) and the South Africa Communist Party (SACP) announced on Tuesday that they were happy with the response to their planned national shutdown, set to take place on September 27.
"This strike is about sending a message to both government and private sector that, as workers and citizens, we are tired of corruption," said Cosatu general secretary Bheki Ntshalintshali.
Adding that Wednesday's march was a chance to stand up against the "cancer of corruption" that was eroding South Africa's gains and undermining its democracy, Ntshalintshali urged employers to allow their workers to participate in the march.
Auditing firm KPMG's woes, and reports concerning the Public Investment Corporation, were also raised by the labour federation and the SACP.
Both organisations claimed that they were worried that Finance Minister Malusi Gigaba would go ahead with attempts to use workers' retirement savings to bail out struggling state-owned enterprises.
"Thousands of jobs at KPMG are now at stake because of the corrupt and greedy tendencies of those who are at the top," said Ntshalintshali.
Cosatu and the SACP have been at odds with their alliance partner, the ANC, for most of the year, with both calling for the ruling party to recall President Jacob Zuma.
'SA is not a poor country, but its citizens are poor'
The labour federation is also backing Cyril Ramaphosa, Zuma's deputy, to take over when he steps down as head of the ANC in December.
The march, which starts outside Cosatu's Braamfontein headquarters at 10:00, will stop at Johannesburg Mayor Herman Mashaba's office, the Department of Labour, the Chamber of Mines, banks in the city centre, and the premier's office, to deliver memorandums.
A total of 13 marches would take place, with Cosatu president Sdumo Dlamini leading a gathering in KwaZulu-Natal.
"South Africa is not a poor country, but its citizens are poor because of poor governance, and as a result of state capture and corruption," said Ntshalintshali.
"President Jacob Zuma is the elite predator. The elite are those who are around him: the Guptas, and those who are inside our movement," said SACP general secretary Solly Mapaila.
He said that the rolling mass action in support of Cosatu was not just another march, but signified an important moment where organised labour came out more clearly to express its disdain and disgust at those who were stealing from the country.
Mapaila called on SACP members serving on the Cabinet to join the mass action.
"They must apologise for not going to Cabinet. If you are working tomorrow, give apologies," he said.