The ANC's unity is in jeopardy, Cosatu general secretary Zwelinzima Vavi said on Tuesday.

"Unfortunately there has not been a great show of unity. In the past two days that's not what the conference has demonstrated in terms of the leadership fighting," Vavi said on the sidelines of the ANC's national elective conference in Mangaung.

"The slate thing is not going to help us... We are quite worried about the slate."

He hoped a winner-takes-all mentality was not adopted. This would mean people on the wrong slate would be sidelined and their talents ignored.

"That will be a tragedy. The winner-takes-all mentality is a recipe for disaster in terms of unity."

The matter needed to be addressed during the African National Congress's discussions on organisational renewal.

"There has to be greater levels of unity in the ANC and greater levels of unity between the ANC and the alliance formation. And you can only achieve that if that discussion on organisational renewal is taken seriously by everybody," he said.

Vavi had been nominated by some structures in the ANC for a position on the national executive committee, (NEC) but declined the nomination.

He said his main reason for declining was because he was general secretary of the Congress of SA Trade Unions and there had to be someone who spoke on behalf of the workers.

This was not the first time Vavi had declined nomination for an NEC seat.

"The ANC members were trying to get the NEC strengthened by getting people like me and others to come in. But I'm sorry that I've disappointed them yet again."