HARARE - South African President Thabo Mbeki is expected in Harare on Monday to continue mediation efforts to break a deadlock in power-sharing talks, a Zimbabwean official said on Friday.

Hopes for a deal have been receding after President Robert Mugabe was quoted as saying he would form a government alone if the opposition failed to sign by Thursday and the opposition said it had lost faith in the talks and Mbeki's mediation.

"President Mbeki will be coming to Zimbabwe on Monday next week to meet all the three parties for further negotiations," Zimbabwean Deputy Information Minister Bright Matonga told South Africa's Talk Radio 702. "We don't have all the details yet."

Talks are deadlocked over how to share executive power between Mugabe and opposition MDC leader Morgan Tsvangirai, putting off any chance of rescuing Zimbabwe from its economic collapse.

Mbeki has come under fire for not being tough with Mugabe. Regional leaders have grown impatient with the deadlock but have failed to persuade the parties to bury their differences. An opposition official said the MDC wanted the African Union and United Nations to rescue the talks.

Analysts believe neither side has much option but to agree a deal.

Tsvangirai has rejected a proposal he says gives Mugabe control of Zimbabwe's powerful security forces.

He beat Mugabe in a March 29 election but fell short of enough votes to avoid a June run-off vote, which was won by Mugabe unopposed after Tsvangirai pulled out citing violence and intimidation against his supporters.

The election was condemned around the world and drew toughened sanctions from Western countries whose support is vital for reviving Zimbabwe's ruined economy.

The smaller, breakaway faction of the MDC, led by Arthur Mutambara, is the third party in negotiations aimed at forming a national unity government.

Zimbabweans are suffering from the world's highest inflation rate of over 11 million percent, and chronic food, fuel and foreign currency shortages that have driven millions over borders and strained regional economies.