The UN is warning of fresh rains and outbreaks of water-borne disease across Africa, where flash floods have already affected more than one million people.

Scores of people have died and hundreds of thousands have been displaced by the floods that have submerged much of the continent's most productive farmland.

The UN said there was an urgent need for food, shelter and medicine.

At least 14 countries have been hit in West, Central and East Africa by some of the worst rains in living memory.

UN spokeswoman Elisabeth Byrs said: "The rains are set to continue and we are really concerned because a lot of people are homeless and infectious diseases could emerge."

"We have 500,000 people affected in 12 countries in West Africa, and also in East Africa - in Sudan and Ethiopia.

"Some of the poorest countries, like Mali, Burkina Faso and Niger - the poorest nation in the world - are badly affected," Ms Brys told the BBC.

The UN said the floods could lead to locust infestations and outbreaks of water-borne diseases such as cholera and dysentery.