A statement from South Africa's Foreign Ministry said Mbeki would meet presidents of Zimbabwean political parties.

President Robert Mugabe's ZANU-PF and the opposition Movement for Democratic Change began talking more than two weeks ago to resolve a crisis that came to a head after the 84-year-old Mugabe was re-elected in a widely condemned June poll boycotted by the opposition.

South Africa's respected Business Day newspaper, citing unnamed sources, said Mugabe and opposition leader Morgan Tsvangirai would hold make-or-break talks to finalise a deal in Harare on Sunday.

Business Day said it was understood the two were not "too far apart", though the central issues remain unresolved.

Mugabe said on Thursday that the talks were going well but dismissed media reports about a draft agreement as nonsense.

Business Day said Mugabe, in power since 1980, and Tsvangirai were said to have been in contact several times during the talks to seek common ground on the delicate issue of power and positions.

The two sides are under heavy international pressure to resolve a deepening crisis that has ruined the once prosperous economy and flooded neighbouring states with millions of refugees.

The Star, a South African newspaper, said on Wednesday that under a draft accord, Tsvangirai would run the country as prime minister while Mugabe would become ceremonial president.