Thirty National Union of Metalworkers of South Africa (Numsa) officials who claim they were suspended so that they could be sidelined ahead of a crucial conference, are headed to the Labour Court on Friday to attempt to have their sanctions lifted.

If this is unsuccessful, they will ask to have the Labour Court in Johannesburg to postpone the union's high-stakes conference at the Cape Town International Convention Center next week, where new national office bearers will be elected.

The 30 officials, including the chairperson of the union in Meyerton, Kwanda Khanyile, and Vereeniging-based official George Makhanya, say that Numsa secretary-general Irvin Jim used suspension to sideline them so that they could not participate in the conference or run for national office.

Jim maintained in a statement released on Monday that these officials were suspended for misconduct and should allow their disciplinary proceedings to run their course before giving their account of events to the media.

He denied suggestions that recent suspensions were about consolidating his support ahead of the conference and said the group was part of a "propaganda" attack which sought to undermine the conference.

The officials are expected to argue in court that the Numsa Central Committee acted beyond their powers according to the union's constitution, by suspending the officials, as well as the union's second deputy president Ruth Ntlokotse.

"We find it ironic that this is the same Numsa leadership that was prepared to collapse the South African Federation of Trade Unions (Saftu) congress if suspended Saftu national office bearers were not allowed to stand for office.

"Now they are proposing to refuse the right of unconstitutionally suspended Numsa shop stewards to even attend their own congress. In our view this is the hypocrisy of the highest order," the statement said.

The group said Numsa's constitution requires that the Central Committee appoint a credentials committee to accredit delegates to the national congress, which was not done.

"No such committee exists. Without this committee, there will be no constitutionally accredited delegates at the congress. Without accredited delegates, there will be no congress/"

Jim said the suspended officials formed a "rogue faction" that sought to undermine democratic centralism within the union.

"These rogue elements are throwing mud and they keep hoping that if they keep spewing out false propaganda, some of it will stick," Jim said.

Ntlokotse was suspended after she was elected as president of Numsa's umbrella federation, Saftu, in May. She has said her suspension was a bid at silencing her within the union, which Jim denies.