Thousands of people were going into a second week in makeshift camps after being made homeless by severe flooding as Sierra Leone was buffeted by torrential rain, the authorities said Wednesday.

Floodwater destroyed houses and swept away property and vehicles as the capital Freetown, an overcrowded coastal city of 1.2 million mainly poor inhabitants, was pounded by torrential rain on Wednesday last week.

The official toll has risen to 10, according to government officials coordinating the clean-up, while an estimated 9,000 survivors were sheltering in tents in the national stadium and another smaller sports arena.

At least 20 neighbourhoods were flooded by the five-hour storm, according to a statement from the presidency, while the city's main hospital was inundated.

Buya Kamara, head of the National Housing Corporation, told reporters 1,000 units would be constructed for flood victims -- but would take three months to complete.

It rains six months of the year in Freetown, one of the world's wettest cities, and putrid water from its populated slopes inundate its coastal slums every summer.

The Ministry of Health warned of the heightened risk of waterborne disease such as cholera that would come with the flooding, vowing to provide 24-hour free healthcare for the sick.

The flooding came with Sierra Leone close to eradicating an epidemic of the tropical Ebola fever which has killed more than 11,000 in west Africa since December 2013.

The virus is particularly dangerous in areas where people live in close proximity as it spreads via bodily fluids, and the National Ebola Response Centre (NERC) said it was screening flood survivors at both stadiums.

"So far, there is no scare and nobody has shown any signs and symptoms of Ebola," said NERC spokesman James Bangura.

"However, since many of the people are from slum areas where Ebola was prevalent... we are monitoring the situation closely."

Freetown residents said they had never experienced rain as heavy as last week's downpours.

"The rains were falling down like marbles," said Fatu Jalloh, who was sheltering inside a tent and eating donated emergency rations at the national stadium.

Femi Smith, a welder rescued from his roof before his bungalow was swept away by raging floodwaters in eastern Freetown, described how he was too traumatised to sleep.

"At night, I keep longing for morning to come. During the flood, I stared at death in the face," he said.

"The only thing I was able to lay my hands on was my dog, Bingo, whom I took with me as I climbed into the attic and tore a hole in the roof. We were sitting on the roof for three hours as household property including TV sets, fridges and beds floated by."