"Areas that (typically) receive more rainfall haven't received much. And once they do, the water from the northern and central parts of the country will feed into streams and rivers and the situation might get worse," Victor Bupe, an official with the country's Meterological Department, said.

One town in a southern province has received its highest rainfall in more than 30 years, the department said.

Zambia's government has appealed for US$13 million in Western aid to deal with the flood crisis. It said on Wednesday it was beginning to assess the damage the rains had caused to bridges, roads, houses and other infrastructure.

There are also fears parts of Zambia could face food shortages as a result of the flooding.

"Most crops have started yellowing due to excessive rainfall. Crops along the river banks in these areas have been washed away," the Meteorological Department said in a statement.

At least six people in Mozambique have died as a result of the floods and officials have warned of outbreaks of diarrhoea and cholera. Diarrhoea is one of the biggest killers of children in Africa.

Floodwaters in Zimbabwe, where millions are struggling to feed themselves in the midst of an economic crisis, have cut road links to large parts of the country.

Heavy downpours are common in southern Africa during the annual rainy season, which runs generally from November to April, but the relentless rain is unusual and has caught officials off guard.

Floods killed 45 people and left 285,000 homeless last year after torrential rain and hurricanes swept through Mozambique.