By Mpho Lakaje
BBC News, Johannesburg
With less than two months to go before the African National Congress elects a new leader, businessman Cyril Ramaphosa is emerging as a compromise contender.
Mr Mbeki and his former deputy Mr Zuma are now bitter rivals
Mr Ramaphosa's name has been put forward by a Cape Town branch of the ANC to challenge for the top job.
Jacob Zuma and Tokyo Sexwale are expected to stand as may President Thabo Mbeki even though he cannot serve a third term as South Africa's leader.
The ANC leader would be expected to become the next president in 2009.
The nomination of Mr Ramaphosa, by the Rondebosch branch in the city of Cape Town, comes in spite of the former unionist's insistence that he has retired from political life.
The 55-year-old former trade union leader was Nelson Mandela's choice as his successor at the head of the ANC.
He was outmanoeuvred by current president Thabo Mbeki and left active politics to concentrate on his investment company Shanduka.
But Mr Ramaphosa remained a member of the ANC executive committee, the party's decision-making body.
He first made headlines when he led mineworkers to one of the country's biggest marches in the 1980s.
Media reports suggest that Mr Ramaphosa was lobbied last week by influential ANC cadres including former Education Minister Kader Asmal.
However he will find himself tussling with his comrade Jacob Zuma for the backing of his former comrades at the Union of Mine Workers.
The union has already announced that it will support Zuma for the hot seat.
Up until now the political battle within the ANC has been dominated by Thabo Mbeki and Jacob Zuma.
Analysts say that could make Mr Ramaphosa an attractive compromise as an alternative candidate.
It is believed that Gauteng Province, which has been divided on a candidate, could come out and back Mr Ramaphosa.
Mr Mbeki has the support of the powerful Eastern Cape while Mr Zuma is backed by the province of KwaZulu-Natal, the ANC Youth League and the Congress of South African Trade Unions.
Some ANC members have urged both men to withdraw from the race because victory for either will sharply divide the ruling party.