In the country's hard-hit west, residents waded through flood waters with their belongings on their heads and evacuated in crowded boats, AFP reporters saw.

Flash floods submerged entire villages in Kisumu county, destroying around 1,200 hectares (3,000 acres) of farmland and sweeping away crops.

More than 3,000 families have been forced from their homes in the community of Nyakach, with some sheltering in eight evacuation centres, locals said, as rising waters from the overflowing River Mirui continue to threaten the community.

"We have lost quite a number of farmlands with massive erosion, and the farm plants that we had planted ," said the chief of Nyakach, Seth Oluoch Agwanda, 57.

The capital Nairobi has the highest death toll in the floods, with 37 people killed, authorities said.

"The cumulative number of fatalities has unfortunately risen to 81," national police spokesman Muchiri Nyaga said in a statement.

"Additionally, flash floods have swept through several areas, displacing approximately 2,690 families and causing widespread destruction of infrastructure and property."

On Friday night, authorities called on residents to evacuate several slum neighbourhoods downstream from the Nairobi dam, warning of an imminent risk of flooding as rising water levels threatened to breach the dam embankment, according to local media.

The dam has held so far.

- 'No house not flooded' -

The rain is forecast to continue until Tuesday.

Authorities called for "extreme caution".

Two people drowned overnight in floods in the town of Kiambu, just outside the capital, police told AFP.

Two also died as landslides hit the western village of Kasaka, burying numerous homes, reported private broadcaster Citizen TV.

The March rains have repeatedly turned Nairobi streets to raging rivers, flooding thousands of homes and businesses.

Critics have called for the resignation of Nairobi Governor Johnson Sakaja, who had vowed to improve the capital's drainage and road infrastructure when he took office in 2022.

In Nyakach, in the west, children walked through knee-high water and residents scooped water from inundated houses -- though some were submerged up to the roof.

""We are migrating because the place where we were staying is badly flooded. We still don't know where we are going to get shelter with our animals because there is no house or home that is not flooded," Kennedy Oguta, 50, told AFP.

Scientists say human-caused climate change is increasing the probability, length and severity of extreme weather events.

Studies indicate east Africa has been hit by more extreme rains and droughts over the past two decades.