Mbeki’s role in the process, now deadlocked over cabinet appointments, has been in doubt since he was ousted earlier this month by his ruling African National Congress after accusations of meddling in the graft case against ANC leader Jacob Zuma.
"He hasn’t made that pronouncement," Thabang Chiloane, a spokesman for Mbeki’s successor, President Kgalema Motlanthe, said when asked if the deposed leader had agreed to keep mediating in Zimbabwe’s political crisis.
Frank Chikane, the director general in the Presidency, was speaking with Mbeki about carrying on as head of the mediation team, the spokesman said.
It is unclear who would fill Mbeki’s shoes if he dropped out.
The former South African ruler helped end conflicts in Ivory Coast and other parts of the continent.
Mbeki faced criticism for not taking a tougher stand on Mugabe. But he scored a coup by mediating a power-sharing deal.
"His appointment as the main facilitator in the political situation in Zimbabwe had nothing to do with his position as President of the Republic of South Africa," said SADC spokesman Charles Mubita.
The talks between Mugabe’s ruling ZANU-PF and the opposition Movement for Democratic Change (MDC) have reached an impasse over who will control key ministries in the unity government to be established under the September 15 power-sharing deal
A meeting between Mugabe and MDC leader Morgan Tsvangirai on Tuesday failed to lead to a breakthrough.
"I don’t think the whole deal is in danger over this, but Mbeki may need to get involved again especially if the deadlock continues for another week or so," said Lovemore Madhuku, chairman of the National Constitutional Assembly (NCA), a political pressure group.
The opposition won a majority of the seats in the March parliamentary election, ending ZANU-PF’s 28-year control of the assembly. Tsvangirai and his officials, however, say ZANU-PF is trying to assign the opposition a junior role in government.
Mugabe’s party has taken a more optimistic view of the talks, saying a deal is imminent and the impasse not serious.
"We need to work together and forego our minor political differences," Augustine Chihuri, the police commissioner-general and a close Mugabe ally, was quoted as saying in the state-run Herald newspaper on Wednesday.