In papers filed in the High Court in Johannesburg, the National Union of Metalworkers of SA (Numsa) called Vavi’s suspension “unconstitutional and unprecedented”.
The Food and Allied Workers’ Union and the SA Football Players’ Union are listed as co-applicants in Numsa’s court action.
According to the papers, the application will be heard on September 10.
Vavi was suspended three weeks ago for bringing the Congress of SA Trade Unions (Cosatu) into disrepute after he admitted to having an affair with an employee.
On September 2, Numsa general secretary Irvin Jim said the union had been forced to take legal action as “Cosatu’s internal and democratic processes are being undermined and flouted”.
He said the decision to legally challenge Cosatu had not been made lightly, and it was not the preferred option of engagement after delegates called for Vavi’s suspension in the February and May central executive committee meetings.
In the court documents, Numsa said the application had been necessitated by a number of contraventions by Cosatu’s national office bearers and the central executive committee (CEC).
The documents detailed events at the CEC meeting which suspended Vavi and provided details on how leaders allegedly disregarded the rules to suspend him.
Cosatu spokesman Patrick Craven confirmed that it had been served with the court papers, and said he could not comment.
“The documents are still with our lawyers who are going through [them] and preparing a response,” said Craven.