Political analysts say the chances of the regional summit breaking an impasse over the allocation of cabinet posts depends on how much pressure the Southern African Development Community (SADC) can put on Mugabe and Tsvangirai to compromise.
Mugabe and Tsvangirai signed an agreement to form a unity government on September 15 under the mediation of former South African President Thabo Mbeki, but this has stalled over a dispute over the allocation of key ministerial departments.
Weeks of negotiations failed to break the impasse and the rival leaders agreed that the SADC should convene an emergency summit on the dispute.
Tsvangirai, leader of the main Movement for Democratic Change (MDC) opposition group, boycotted the first summit in Swaziland a week ago, saying Mugabe’s government had refused to grant him a passport and instead gave him only an emergency travel document to attend the talks.
On Monday, Tsvangirai will join Mugabe, Arthur Mutambara of a smaller MDC faction, Mbeki and leaders from South Africa, Swaziland, Angola and the Democratic Republic of Congo at the rescheduled summit in Harare.
Tsvangirai, set to become prime minister if a power-sharing government takes office — says he will not be bullied into an administration in which he will have little authority.
He accuses Mugabe of trying to make him a junior partner with control over less important ministries.
In turn, Mugabe’s ZANU-PF accuses Tsvangirai of seeking a power transfer, not a power-sharing arrangement, and of stalling the talks to try to drag in the United Nations to mediate.
"On the face of it, you get an impression there will be no deal, but it’s a 50-50 affair," said Lovemore Madhuku, chairman of the National Constitutional Assembly, a political pressure group.
"I think both parties realise that the region, and that many Zimbabweans want some kind of settlement," he told Reuters.
"But the greater pressure will be on Tsvangirai because many SADC leaders believe that Mugabe has already climbed down low enough."
In the past Mugabe, who is 84 and has been Zimbabwe’s sole ruler since its independence from Britain in 1980, has vowed that Tsvangirai will never get near power.
Mugabe dismisses Tsvangirai as a "pathetic Western puppet" while the 56-year-old opposition chief calls him a "raving old man with nothing to offer".
John Makumbe, a veteran political commentator and Mugabe critic, said Monday’s meeting would fail if SADC leaders resorted to their traditional support for Mugabe.
"It is Mugabe who needs pressure not Tsvangirai, and it is the people of Zimbabwe and the Zimbabwe economy who need the support of SADC to survive," Makumbe said.
Political analysts say the September 15 power-sharing agreement is Zimbabwe’s best hope for rescuing an economy in free-fall, with fuel and food in scarce supply while inflation stands at 231 million percent.