The government said in a statement it needed international help to repair roads, bridges and provide humanitarian assistance after heavy rains in neighbouring Angola led to devastating floods.

"Namibia is gravely concerned over the destructive impact of the forces of nature that first brought a drought, and now severe floods," President Hifikepunye Pohamba told reporters.

Gabriel Kangowa, head of the country's emergency management unit, said 4,500 people had been made homeless in central and northern Namibia by a month of flooding.

The rain in Angola turned normally dry floodplains -- known as "oshonas" -- into raging rivers, washing away roads and bridges and forced the closure of scores of schools in the northern Owambo region.

Most of the victims were young children or old people who appeared to have drowned when crossing floodplains at night.

"People are used to walking through the oshonas, but this time they are much deeper than before. We have had lots of drownings at night, when people can't see where they are going," Kangowa said.

Guido van Langenhove, Head of Hydrology in Namibia, said more floods could be expected as Angola's southern Cunene province had received non-stop rain for the past three weeks.

"The Cuvelai area is a disaster, the floods are at the highest level we have seen in over 35 years," he said, referring to an area in Angola just north of the Namibian town of Oshakati.

He said more floodwater was on its way into already flooded areas in Namibia, adding: "The end is not yet in sight".

Emergency management chief Kangoma said some 250,000 people in the densely populated Owamba region have been cut off with many only reachable by helicopter.

In the eastern Caprivi region, rescue officials have begun evacuating schoolchildren by boat across the rising Zambezi River into Zambia, and from there, by road back to Namibia.

The Zambezi, which normally only reaches its highest levels towards April, was currently at record highs, Van Langenhove said.

The U.N. Children's Fund said last month that close to 150,000 children in southern African were in need of humanitarian assistance because of floods.

At least 45 people have died in Mozambique, Zambia, Zimbabwe and Malawi since torrential rains swept through southern Africa in December and January. The subsequent floods have swept away livestock and crops, prompting fears of food shortages and outbreaks of disease.