Johannesburg - The red carpet was rolled out at a hotel in Zimbabwe's capital Harare Monday ahead of the signing, scheduled for later, by President Robert Mugabe and opposition Movement for Democratic Change (MDC) leader Morgan Tsvangirai of a key agreement on talks.

The city's Rainbow Towers Hotel was the neutral venue chosen for the signing ceremony, at which Mugabe will represent his Zanu-PF and Tsvangirai will sign on behalf of his MDC faction.

The third party to the agreement is Arthur Mutambara, leader of a smaller MDC faction.

The memorandum of understanding sets out the agenda for talks between the three parties on a powersharing government, as called for by the African Union at a summit in June.

South African President Thabo Mbeki, southern Africa's mediator in Zimbabwe, was on his way to Harare Monday to oversee the signing, the foreign affairs department in Pretoria said.

Achieving Tsvangirai's agreement on the document is seen as a coup for Mbeki's mediation after the MDC leader rebuffed Mbeki's first attempt, a few weeks ago, to kickstart talks between him and 84-year-old Mugabe.

On Friday, Mbeki dismantled one of the last hurdles to the start of the talks by expanding his mediation to include representatives from the United Nations and the African Union, in line with Tsvangirai's demands.

Mugabe and Tsvangirai have been asked by the 53-member African Union to form a government of national unity to end a months-long, violent standoff between the two parties in the wake of March elections.

Although the MDC won the parliamentary component of those elections and Tsvangirai topped the poll in the presidential vote, Mugabe, 84, was sworn in as president for a further five years in June following a run-off election he alone contested.

Tsvangirai boycotted the election after dozens of his supporters were killed by ruling party militia in the run-up to the ballot. (dpa)