Joahnnesburg - National Union of Metalworkers of SA (Numsa) general secretary Irvin Jim criticised the ANC's Gwede Mantashe and the SACP's Blade Nzimande, accusing them of dividing Cosatu, The Times reported on Tuesday.
"Him [Mantashe] and Blade are doing everything to divide Cosatu unions," he reportedly said.
Speaking at a Numsa march in Randburg on Monday, Jim said Numsa would not seek advice from African National Congress secretary general Mantashe and SA Communist Party general secretary Blade Nzimande on federation matters.
"No, we take our mandate direct from metalworkers. We want to tell Mantashe that we are watching his poisonous tongue."
On Tuesday, the High Court in Johannesburg will hear a Numsa application to have Congress of SA Trade Unions general secretary Zwelinzima Vavi's suspension overturned.
Vavi was suspended last month on accusations of bringing Cosatu into disrepute after he admitted to having an affair with an employee.
Mantashe last week said that a "cult of personalities" created problems for Cosatu.
On Sunday, the SACP called on Jim to provide evidence of his previous claims of factionalism.