The Congress of South African Trade Unions (COSATU), South Africa's largest union group, had called for the protest marches to be held across cities in South Africa, citing rampant corruption in President Jacob Zuma's government as well as several businesses affiliated with the influential Gupta family.

In Johannesburg alone, roughly 2,000 members of COSATU took to the streets, waving placards reading "Zuma must go — corruption is a crime against humanity."

Read more:South Africa's ANC in crisis

Other signs read "State capture is a criminal offence," referring to the raiding of taxpayers' funds by outside interests — known locally as "state capture."

COSATU, which is in a tripartite alliance with Zuma's ruling African National Congress (ANC) and the South African Communist Party (SACP), has broken ranks and demanded that the president step down. It now officially backs Deputy President Cyril Ramaphosa.

Corruption allegations

The union group accuses Zuma of appropriating state funds on an enormous scale, as well as colluding with the influential Gupta family,who have been implicated in many of the graft allegations against the president.

Zuma denies all allegations of corruption. Although criticism is mounting, he is not immediately threatened by the strikes, as he still has the support of powerful factions within the ANC and he has survived a series of parliamentary votes of no-confidence.

The Gupta family have also denied wrongdoing, but several international firms affiliated with them have run into trouble.

The London-based law firm Bell Pottinger went into administration after being thrown out of the trade body of the British public relations industry. An investigation showed it had conducted a racially divisive publicity campaign on behalf of the Guptas' Oakbay Capital company.

The global consultancy KPMG investigated work that it did for the Guptas and reported that it found "work that fell considerably short of KPMG's standards," leading it to dismiss its CEO for South Africa.

Zuma is set to hand over the reins as head of the ANC at a party congress in December. His term as president runs out after the elections in 2019.

ng/mkg (AP, AFP)