Malawi's electoral authorities said they would reopen ballot boxes after finding evidence of irregularities, as the country was thrown into a constitutional crisis over its disputed poll.
"In the course of vote tallying, there are cases being discovered where the total number of votes cast is more than the total registered voters for the centre," Maxon Mbendera, chairman of the Malawi Electoral Commission, said in a statement on Sunday.
"It has been agreed with political parties that this can be resolved by opening the ballot boxes and doing a physical audit," he said.
The recount could start this week after an implementation plan was thrashed out on Sunday with political parties.
On Saturday, Malawi's President Joyce Banda declared the election "null and void", claiming there were "serious irregularities" with the poll.
She issued a decree that vote counting should stop and called for fresh elections in 90 days.
But just hours after her announcement, Malawi's high court issued an injunction preventing the president from annulling the poll.
Riot police on alert
Banda alleged that people had voted multiple times, ballots had been tampered with, presiding officers arrested, and the computerised voter counting system collapsed, but her main rival Peter Mutharika called the decision to annul the election "illegal".
A heavy police presence continued on Sunday in the commercial capital of Blantyre, with scores of riot police on alert at the tally centre.
The country's electoral commission said it had counted 62 percent of the votes from half of the 4,445 polling centres spread throughout the tiny southern African state.
Ken Msonda, spokesman for Banda's People's Party, told AFP news agency: "We have been vindicated as a party. Malawians will definitely know the truth now. we are still in the game after the recount."
Nicholas Dausi, a spokesman of Peter Mutharika's Democratic Progressive Party, said they will dispute the vote recount.
"There is no security and safety of the ballot boxes," he told AFP.
With about a third of the votes counted, Mutharika, 74, had 42 percent of the vote, while Banda has 23 percent, according to preliminary results announced by the electoral commission late on Friday.
Mutharika is the brother of late president Bingu wa Mutharika, who died in office two years ago.
On Saturday he did not claim victory but said the "people have spoken and this was a free and credible election".