Tsvangirai was flown to neighbouring Botswana on Saturday to recover from the accident and to undergo another medical check-up, but is expected to return to Harare late on Monday, the official, who asked not to be named, told Reuters.
"The arrangement is that Mrs Tsvangirai will be buried on Wednesday in her rural home of Buhera," he said. A procession commemorating her would be held in Harare on Tuesday.
Tsvangirai, who left hospital in the capital on Saturday, has suffered head and neck wounds, but is in stable condition, other officials said.
Police have launched an investigation into the accident, which took place on Friday on a potholed road south of Harare.
Tsvangirai’s MDC said they would conduct their own probe to see whether foul play was involved. The party said the crash could have been avoided if proper security had been in place.
The truck that collided with Tsvangirai’s car belongs to the United States Development Agency and was carrying British and U.S. aid. The British government said it believed the crash to be a "genuine accident", according to media reports.
The prime minister and his arch rival, President Robert Mugabe, formed a power-sharing government in February after months of negotiations to try to end a political and economic crisis that has brought Zimbabwe to ruin.
Tsvangirai, who turns 57 on Tuesday, had six children with Susan, who was popular among MDC supporters, who would chant "mother, mother" when she appeared at rallies with her husband.
Susan, 50, avoided the spotlight but stood by Tsvangirai throughout his ordeals as Mugabe’s most determined opponent.
Tsvangirai’s wife, Susan, was killed when a truck veered into the opposite lane and slammed into their vehicle. She was thrown out of the car, which overturned and rolled three times, and was pronounced dead on arrival at hospital.
Tsvangirai suffered some head and neck wounds, but his condition was stable, Biti said.
"Mr Tsvangirai is stable, but he’s in physical pain. The physical pain is dwarfed by the loss of his wife," he said.
Tsvangirai is expected back in the country on Monday. The driver of the truck, which belongs to the United States Development Agency, is in police custody.
Mugabe, who visited his old rival in hospital, said on Saturday the accident and the death of Tsvangirai’s wife were a blow to a nation celebrating a new power-sharing government.
"We were celebrating this major development when the tragedy struck. It is very sad indeed," Mugabe said.
Tsvangirai and Mugabe formed a unity government in February after months of talks to try to end a political and economic crisis that has brought Zimbabwe to ruin, with food shortages, a cholera epidemic and the world’s worst hyperinflation.
Several world leaders offered condolences to Tsvangirai, among them South African President Kgalema Motlanthe.
Tsvangirai, who turns 57 on Tuesday, had six children with Susan, 50. She was very popular among MDC supporters who would chant "mother, mother" when she appeared at rallies.
"She was a people’s hero. She was a mother to us and to our struggle," MDC’s Biti said in a statement.
She avoided the political spotlight but stood by Tsvangirai throughout his struggle as Mugabe’s most determined opponent.