South African President Thabo Mbeki held talks with his Zimbabwean counterpart, Robert Mugabe, on his arrival in Harare Monday, where he hopes to inject new momentum into stalled multi-party talks on a power-sharing government.

Mbeki, the 15-nation Southern African Development Community (SADC)-appointed mediator in Zimbabwe, is on his second trip to Zimbabwe in as many months as he tries to resolve a dispute between Mugabe and Movement for Democratic Change leader Morgan Tsvangirai.

The two men are at loggerheads over how to share power in a unity government.

Mbeki entered talks with Mugabe at a city-centre hotel and was expected to meet Tsvangirai later. The third party to the talks is a breakaway faction of the MDC led by Arthur Mutambara.

This visit by Mbeki is devoid of the anticipation that surrounded the last round of talks he brokered between Zimbabwe's leaders in early August. Those talks broke off after Tsvangirai balked at a deal that would have seen Mugabe retain much of his powers.

A recent summit of SADC leaders in Johannesburg and a later round of talks in South Africa failed to end the deadlock.

"The issue is about the constitution which gives too much power to the president," MDC Secretary-General Tendai Biti told a rally in Gweru, 300 kilometres southwest of Harare, on the 9th anniversary of the MDC's founding.

"We need an interim constitution that deals with that," he said.

Mugabe has threatened to forge ahead with forming a government without the MDC, unless Tsvangirai signs up to a deal that would make him prime minister but without the full powers of a head of government.

Tsvangirai on Sunday reiterated his belief that no deal was better than a "bad deal." His party has the most seats in the lower house of parliament, making it difficult for Mugabe to govern without him.

Tsvangirai also gained more votes than Mugabe in March elections but failed to pass the 50 per cent threshold to unseat the authoritarian leader.

The MDC, the West and a handful of African countries refused to recognize Mugabe's victory in a run-off ballot at the end of June that Tsvangirai boycotted over a spate of killings of his supporters.

Zimbabweans see a negotiated political settlement as the only panacea for the country's decade-long political and economic woes.

Mugabe's populist policies are widely blamed for inflation of 11.3 million per cent, widespread food, fuel and drug shortages and mass emigration.