Johannesburg - Cosatu is holding what is seen as a crucial central executive committee (CEC) meeting where it is expected to take a decision on where it stands on the ANC's succession debate.
"There are no two ways about it, we have to take a view on the succession debate, after [it] was deferred to this CEC. The last CEC asked affiliates to go and consult," an affiliate leader who did not want to be named told News24.
The CEC starts on Monday and continues until Wednesday.
Two unions, the largest affiliate the National Education Health and Allied Workers Union (Nehawu) and the Communication Workers Union (CWU) have already come out publicly calling for President Jacob Zuma to step down, and others, including Police and Prisons Right Civil Union (Popcru) and the South African Democratic Teachers Union, are expected to follow.
Nehawu and the National Union of Mineworkers (NUM) have backed Deputy President Cyril Ramaphosa to take over the reins.
The debate has been raging in Cosatu for some time now, amid fractured relations between the trade union federation and its alliance partner, the ANC.
Earlier this month, the federation released a strongly worded statement calling on the "arrogant" ANC to stop treating them with "disdain".
"Cosatu is concerned that its ally, the ANC, is starting to treat the support of the workers with disdain and takes the loyalty of the federation for granted," the statement read.
Affiliates have been calling for a hardened approach to the ANC, frustrated that the governing party has not delivered on key worker demands including the banning of labour brokers, the scrapping of e-tolls, the slow progress in implementing the national health insurance scheme and a comprehensive social security plan.
Some affiliate leaders have accused Cosatu president Sdumo Dlamini, seen as a staunch ally of Zuma, of stalling the ANC succession debate.
Another affiliate leader told News24 that this week's meeting might be about how the federation manages the succession debate and whether Cosatu will publicly pronounce that it supports Ramaphosa.
The Tripartite Alliance council meeting held at Luthuli house earlier this month failed to assure Cosatu leaders. Instead, they were blamed for the dismal performance of the ANC in the local government elections.
CWU wants the marriage between alliance partners ANC, SACP and Cosatu to be reconfigured and Cosatu to be cautious this time around when backing a candidate.
"We've been told that the alliance was never written, this time it must be written so that there are clear terms of reference and guidelines," president Clyde Mervin told journalists at a media briefing last week.
Goals and roles
The CWU said it was going to the central executive committee seeking to get support in this regard because it wants to spell out the goals and roles of the members of the alliance.
"It cannot be open-handed anymore, it must be written down so that the working class can be protected in the process."
The union said its members were now taking part in the ANC succession debate but its leaders had already concluded that Zuma's time was up.
Ramaphosa is expected to get support at least from the largest affiliates, but others want assurances that he will deliver on their key demands.
CWU said it would only favour a candidate who "put the workers' rights first".
Ramaphosa is currently leading talks around the minimum wage.
Cosatu was instrumental in Zuma winning the 2007 and 2012 elective conferences.
Last year it expelled Numsa and general secretary Zwelinzima Vavi which was its largest affiliate for its 2013 conference resolution not to endorse the ANC in the 2014 election.