KHARTOUM - The worst floods in living memory in Sudan have killed 150 people, made hundreds of thousands homeless and cost the country an estimated $300 million in damages, a Sudanese official said on Thursday.

Heavy and early winter rains have caused flash floods and forced rivers to burst their banks in Africa's largest country, which has been recovering from decades of multiple civil wars. Most people live along river banks in the mostly desert country.

"We have about 73,000 houses completely destroyed and 29,000 partially destroyed," said Hamadallah Adam Ali, head of Sudan's civil defence authority.

He said 150 people had been killed and 302 injured by the flooding, with 42,000 livestock lost.

Ali said that 1,748 public buildings had been damaged, estimating the total losses at $300 million.

"These are the worst floods in Sudan. There has been no flooding like this in years," he said.

Many roads and bridges have been cut off and the World Food Programme said it was airlifting food and relief supplies to flood victims in remote areas of southern Sudan.

Ali said Sudan needed help to compensate all the victims. "The United Nations has to help us rehabilitate," he said.

This week the world body said only $1 million of an appeal for $20 million had been received from donors.

Sudan's multiple conflicts in the south, east and western Darfur regions have drained around $1 billion a year of donor cash for humanitarian and reconstruction efforts.

On top of that, a new joint U.N.-African Union peacekeeping force for Darfur will cost more than $2 billion a year and a separate U.N. peacekeeping force in the south cost more than $1 billion in its first year.

Sudan produces more than 500,000 barrels per day of crude oil.