South Africa’s powerful trades union federation Cosatu has called for President Jacob Zuma to step down.
Its Secretary General Bheki Ntshalintshali said he was no longer the “right person” to lead the country.
Anti-apartheid struggle veterans have also called on the African National Congress (ANC) to recall the president.
Mr Zuma has been under growing pressure following a major cabinet reshuffle which included the sacking of respected Finance Minister Pravin Gordhan.
That led to South Africa’s credit rating being cut to junk status putting more pressure on a troubled economy.
The Congress of South African Trade Unions (Cosatu), a key part of the governing alliance, says it has 1.8 million members.
It forms part of what is called the Tripartite Alliance along with the the African National Congress (ANC) and the South African Communist Party (SACP).
The SACP has also called on Mr Zuma to go.
Cosatu General Secretary of Bheki Ntshalintshali told a media briefing that the union’s decision was driven by Mr Zuma’s failure to consult it before making changes to his cabinet.
Image copyright Reuters Image caption Demonstrators came out in the capital, Pretoria, in response to the news of Finance Minister Pravin Gordhan’s sacking last week.
He termed the president’s leadership as “inattentive, negligent… and disruptive”.
He added that the organisation was not concerned about Mr Gordhan’s sacking because he was, like his predecessors, “not a friend of the workers”.
“We will support the new minister where necessary and fight with him where necessary,” he added.
Mr Ntshalintshali also criticised ratings agency S&P’s decision to downgrade South Africa to junk status saying the union views it as political interference.