Diplomatic sources today say Mbeki planned to meet Mugabe, Tsvangirai and Arthur Mutambara, who heads a breakaway faction of the MDC.

“Mbeki will be in Zimbabwe on Wednesday for the talks . He realises the need for an urgent deal in the country to avert a humanitarian crisis,” one of the diplomats said.

The planned trip to Harare will be Mbeki’s first major move to push for a political settlement in Zimbabwe following a weekend summit of leaders of the Southern African Development Community (SADC) that failed to flog Mugabe’s ruling ZANU PF party and the MDC into signing a power-sharing pact.

Mbeki, who assumed the rotating chairmanship of SADC, spent four days in Zimbabwe last week trying unsuccessfully to nudge Mugabe, Tsvangirai and Mutambara to form a government of national unity.

ZANU PF and MDC officials privately confirm that Mugabe and Tsvangirai agree on nearly all the other aspects of a unity government but sharply differ over who between them should wield more power.

Tsvangirai wants to be executive prime minister with Mugabe serving as ceremonial president.

But Mugabe is unwilling to shed any of his wide-sweeping powers and has instead offered to make Tsvangirai a non-executive premier.

The two rivals also differ on the duration of the unity government with Tsvangirai saying it should last up to two years while Mugabe prefers the government to serve a full five-year term.