They quote a senior government source.
It is unclear if he has already left for Zimbabwe and when he will arrive in the country.
Meanwhile, there are reports that the governing Zanu-PF party will proceed to discuss the impeachment of President Robert Mugabe after his resignation deadline lapsed.
The party’s chief whip Lovemore Matuke told Reuters news agency the party’s MPs had planned to meet today.
Reuters has a faster estimate – saying that, because of the overwhelming support for the removal of Mr Mugabe, it could take a day.
It quotes John Makamure from the Southern African Parliamentary Support Trust saying the move could take 24 hours:
“They can fast-track it. It can be done in a matter of a day.”
Also trending: The leader of Zimbabwe’s main opposition party has said that an inclusive government should be formed to see the country through the political crisis, the Reuters news agency reports.
Morgan Tsvangirai, who leads the MDC party, also said that people from different sectors should be involved in planning for the country’s future.
He added that next year’s election should be supervised by the international community.
Mr Tsvangirai, a long-time political rival of Mr Mugabe, added that the veteran leader’s refusal to resign had “dampened people’s spirits”.