Nelson Mandela is engaged in a campaign to open up space for debate in the African National Congress ahead of the party's national conference in December, sources close to the former president claim.

In the past few weeks Mandela has engaged in a host of media interviews and private discussions, including with opposition leader Tony Leon. He has raised key issues causing divisions in the ANC, including its relationship with the South African Communist Party, its policy on HIV/Aids and its approach to Zimbabwean leader Robert Mugabe. All of them are areas in which President Thabo Mbeki is considered vulnerable to criticism.

During the World Summit on Sustainable Development Mandela stole much of the limelight from Mbeki, meeting a string of foreign leaders and making critical comments on the proposed United States attack on Iraq.

This week he launched a carefully worded but public defence of the SACP in an interview published in the 'Sowetan' -- and gave notice that he would be raising a number of issues at the December conference, most notably the government's stance on HIV/Aids.

Questioned about the government's stance on HIV/Aids -- widely seen as driven by Mbeki -- Mandela said he did not want to "criticise my government publicly. My duty is to raise all my concerns, confidentially and privately, in the meetings of the officials of the National Working Committee and the National Executive Committee [NEC]. If I don't get support, then I can go to the national conference."

Privately, Mandela is also understood to have recently raised concerns about the Mbeki presidency. Nevertheless, it is unlikely that anyone will directly oppose Mbeki's reappointment as ANC president.

"I don't see anyone raising his head above the parapet unless Mandela approaches one of them," a source said.

Others have questioned the impact Mandela may have.

Another ANC insider said while nothing was likely to change in the top positions, many of the old guard on the NEC would lose their positions -- a change that could alter the balance of power at a leadership level. But something similar happened at the 1997 conference and Mbeki proved well able to deal with an NEC initially regarded as fairly hostile to him.

"Thabo, [Deputy President Jacob] Zuma and Kgalema [Motlanthe, the ANC secretary general] are safe. Anyone trying to stand against Zuma will be destroyed," said the source.

Zuma is the one to watch, say insiders. The Mbeki camp has repeatedly flighted possible candidates to challenge him as deputy president, such as Patrick Lekota, Motlanthe or Zuma's former wife, Nkosazana.

It is understood it was Zuma who privately persuaded Jeremy Cronin to apologise, arguing that confrontation between the ANC and the SACP would play into the hands of Mbeki supporters at the December conference.

'Africa Confidential' editor Patrick Smith says there are persistent rumours about what he calls "the ANC 'dissidents'", such as Pallo Jordan, Tokyo Sexwale, Cyril Ramaphosa -- those who held power during the Mandela era.

"There is a question asked as to how long they will remain silent or when will they find the vehicle to act."

Others have ruled this out, however, at least until the battle for 2009, when Mbeki will have served his maximum two terms. But there may be an attempt before then to "clip Mbeki's wings" on the domestic front, while allowing him to pursue the New Partnership for Africa's Development and the African Union.

"Zuma is not a final choice for succession," says political scientist Adam Habib. "I think the party will postpone that decision."

Former ANC activist Trevor Ngwane, says the fact that Mandela has had to go around "acting the militant activist" on behalf of the party grassroots was an indication of the serious erosion of internal party democracy.

"But you can't dismiss the conference. The ANC alliance is in a crisis. The dominant ANC faction -- the black emergent bourgeois faction -- doesn't have a problem, except for their legitimacy. But for the alliance partners there is a big crisis. This conference might be their last chance to do anything significant. But if they try to use this conference to take him on, Mbeki will smash them."

A very senior union source says the struggle for the core values of the alliance -- and hence of the direction of the South African democratic project -- was becoming visible.

Up to now, ANC policy had accepted that the black working class stood at the centre of both the driving and the benefits of transformation. But, the source said, the Congress of South African Trade Unions believed the attempt by the ANC to place black economic empowerment at the centre of transformation had shifted the balance in favour of the emerging black middle class.