Johannesburg - The National Union of Metalworkers of SA (Numsa) wants the ANC to lose the election, Cosatu said on Tuesday.
"This cannot be done in the name of Cosatu," Congress of SA Trade Unions acting general secretary Bheki Ntshalintshali told reporters.
He said Numsa leadership was pursuing an agenda aimed at destroying Cosatu, the African National Congress and the SA Communist Party.
This programme was aimed at ensuring Cosatu was weakened, and at ensuring the ANC lost the election and that the SACP was liquidated, "so that all these formations can be replaced by the Numsa and its allies", he said.
Ntshalintshali said that as long as Numsa was a Cosatu affiliate it had to abide by its constitution and policies.
At a special national congress in December, Numsa resolved that it would not support the ANC in the May 7 national election, and would also not fund the ANC's election campaign.
Cosatu is in an alliance with the ANC and the SACP. Numsa has also called on Cosatu to break away from the alliance.
Numsa and Cosatu have been at loggerheads since the suspension of the federation's general secretary Zwelinzima Vavi.
Cosatu has threatened to suspend or expel Numsa. It gave the metalworkers union until Thursday to explain why it should not be expelled or suspended.
On Sunday, Numsa said it would respond to Cosatu within the required time frame.
Vavi was suspended last year, following revelations of an improper sexual relationship with a junior staffer. He also stands accused of a raft of allegations relating to the sale of Cosatu’s old headquarters and the purchase of its new building.
Numsa has called for his reinstatement, and has led nine other unions in a call for a special congress.
Cosatu president Sidumo Dlamini said Cosatu would not abandon its allies.
"We are not going to dump the ANC. We are not going to do that... the worst we could do is to dump our allies."
He said that for the federation to convene a special congress it would need R10m, for which there was no budget.