Under-fire South African President Thabo Mbeki pushed ahead with efforts to broker an end to Zimbabwe's crisis Friday, hosting talks with the African Union's top official and a UN troubleshooter.

Mbeki, heavily-criticised over his policy of quiet diplomacy towards his Zimbabwean counterpart Robert Mugabe, was locked in talks with AU Commission chairman Jean Ping at his office in Pretoria after a similar session with the United Nations' special representative to Zimbabwe, Haile Menkerios.

The closed-door talks were being held ahead of a gathering of foreign ministers in the city of Durban, where Zimbabwe's post-election violence and efforts to bring about some kind of power-sharing deal were to top the agenda.

While Mbeki posed with Menkerios and then Ping at the start of their meetings, he was tight-lipped on what they would discuss.

While little fanfare has surrounded the get-together, it is the first between Ping and Mbeki since Mugabe's re-election in a one-man poll on June 27.

The ballot was widely denounced as a sham in the West after the leader of the opposition Movement for Democratic Change, Morgan Tsvangirai, boycotted the run-off following a wave of deadly attacks on his supporters.

Mbeki has been trying to mediate between the opposition and Mugabe's ruling ZANU-PF party but, having made little headway so far, has faced calls to be either axed from his role or at least to begin working in tandem with the AU.

"The MDC has made it clear an expanded (mediation) team provides the best opportunity for a negotiated solution to the Zimbabwe crisis," a source close to Tsvangirai told AFP.

"The situation in Zimbabwe is deteriorating on a daily basis and it is essential for the people's welfare that a transitional agreement is reached as soon as possible and we hope the outcome of today's consultations will facilitate this."

The MDC and ZANU-PF began preliminary talks last week aimed at establishing a framework for substantive negotiations.

Tsvangirai, who beat Mugabe into second place in the first round of voting in March and does not recognise his old rival's re-election, has so far refused to put his name to a framework deal -- although his aides have hinted he will be ready to sign after the Ping-Mbeki talks.

Mbeki was tasked more than a year ago by the 14-nation Southern African Development Community (SADC) to mediate between the MDC and ZANU-PF, and was asked to push ahead with his efforts at a summit in April.

His Foreign Minister Nkosazana Dlamini-Zuma was to give an update on the mediation efforts at Friday's meeting in Durban, with the South African government insistent that a resolution to the Zimbabwe crisis remain the sole preserve of SADC.

"Our view has always been, and I am stressing it, we are being diverted by a fake argument about the expansion of the SADC facilitation," Deputy Foreign Minister Aziz Pahad told reporters earlier this week.

"I don't believe that at this very crucial moment, adding new bodies, simply to sit in the same room, is what is required," he added.