Mbeki’s role had been thrown into doubt after his ruling ANC forced him to resign last month, shortly after he had negotiated a breakthrough framework agreement for Zimbabwe in mid-September.
"He will resume as soon as it is practically possible," spokesman Mukoni Ratshitanga told Reuters.
Zimbabwe’s opposition MDC says only mediation can break a deadlock in talks on forming a cabinet. Pressure for Mbeki to return as mediator has grown as Zimbabwean President Robert Mugabe’s ZANU-PF and the Movement for Democratic Change (MDC) have remained far apart over how to carve up cabinet posts.
ZANU-PF said this week it did not see any immediate need for mediation.
But Patrick Chinamasa, chief ZANU-PF negotiator in the talks, said on Friday the party welcomed Mbeki’s continued mediation.
"We are obviously happy that he will continue in that role," he told Reuters.
The negotiations have reached an apparent impasse over who will control key ministries in the unity government to be established under the deal.
The opposition accuses Mugabe’s party of trying to assign it a junior role in government.
Mugabe, who has ruled since independence from Britain in 1980, had expressed confidence the cabinet would be named this week. But Tsvangirai and his officials say a deal is not imminent.
Without a breakthrough, Zimbabwe’s economy could worsen still further. The once-prosperous nation is crumbling under inflation of about 11 million percent — the highest in the world — and chronic food shortages.