SACP general secretary Blade Nzimande made a passionate plea to Cosatu yesterday not to abandon embattled ANC secretary-general Gwede Mantashe.

Mantashe is under fire from ANC Youth League president Julius Malema, who wants him replaced by Sports Minister Fikile Mbalula at the ruling party's next congress.

Though Mantashe is a former unionist, there have been growing tensions between him and senior Cosatu leaders, who accuse him of being "too harsh" in his criticism of organised labour.

In a hard-hitting speech to Cosatu's 5th Central Committee meeting yesterday, Nzimande also warned about the wholesale nationalisation being punted by the youth league.

"Stop harassing Gwede. He is part of us, he is our own. Do not mess with Gwede," said Nzimande to loud applause from about 900 delegates.

Nzimande also spoke about the dangers of factionalism that have taken root within the ANC and the alliance, and said it was damaging the organisations.

"The ongoing factionalism within the ANC and across the alliance is costing us. Going forward, it will also be important that we, as alliance partners, deal frankly and constructively with the issues that have the potential to divide us."

He warned of an emerging "new tendency" within the alliance that was threatening unity and called on leaders to close ranks.

In a clear reference to the youth league and those supporting its call on change of leadership, Nzimande said the group represented the most immediate tactical threat to the struggle.

He also lashed out at the youth league's "anti-white" statement made during the May elections campaign.

"Demagogic anti-white utterances and theatrical parading with sub-machine-gun-toting heavies fuelled the DA campaign, not just in the white community, but also in other so-called minority communities - with the DA appealing to a sense of minorities under threat," Nzimande said.

His call for unity was echoed by President Jacob Zuma and Cosatu president Sdumo Dlamini.

But yesterday, Cosatu general secretary Zwelinzima Vavi said he was unhappy that there were divisions within the alliance.

Vavi said Zuma's lukewarm reception by delegates on Monday was a sign that all was not well.

"I think a lot of people were saying we do not like where we are now. What people are asking for is more decisiveness from the president especially with regard to the youth league."

In his address about nationalisation, Nzimande questioned the persistence of making nationalisation a government policy.

"Nationalisation is but one way of achieving this overall objective, but nationalisation is not inherently progressive, as it depends on whose class interest it is advancing."

The communist party boss also called on the ANC alliance to deal urgently and decisively with ill-discipline and factionalism associated particularly with the new tendency.

Malema recently attacked the SACP, saying the vanguard only existed in office and had now turned into a lobbying group in the ANC instead of dealing with the issues of the working class.

Nzimande further claimed that the ANC national general council last year exposed the demagogic vanguard of the new tendency and its style of politics, which was rejected by the majority of ANC delegates.