Vavi would return to work on Monday after the South Gauteng High Court in Johannesburg set aside his suspension on Friday.
Vavi was put on special leave in August last year, pending the outcome of a disciplinary hearing relating to his affair with a junior employee.
Following Vavi's suspension Numsa, an ally of his, lodged an application in the high court challenging the decision.
Cosatu had been split between affiliates supporting Vavi and those supporting his suspension.
However, it emerged at a National Union of Metalworkers of SA shop stewards council at the Coastlands Hotel in Durban on Sunday that Vavi could face suspension from the federation again.
"On Tuesday they will say ‘let us continue with the disciplinary charges against Zwelinzima Vavi’," Numsa deputy president Karl Cloete said at the council.
He said that the current office bearers of Cosatu should be held accountable for wasting workers' money on hiring expensive lawyers to fight against Vavi's reinstatement.