By Emma Jane Kirby BBC, Geneva

The World Food Programme (WFP) has launched an appeal for $308m for Southern Africa, warning that at least 6.5m people will still be dependent on food aid for another year.

Some 25% of people are HIV positive in several Southern African countries

Speaking in Geneva, the United Nations agency said although the major humanitarian crisis they had feared has now been averted, erratic weather patterns, deteriorating economies and the devastating impact HIV/Aids is having on communities means that needs remain substantial.

WFP says at least 500,000 metric tonnes of food is needed for Southern Africa over the next 12 months, despite the fact that some countries, like Malawi and Zambia, have produced significantly better harvests this year.

The continuing food crisis mainly affects Zimbabwe, Mozambique, Lesotho, Swaziland, Malawi and Zambia.

Food fights Aids

Two-thirds of the aid will go to Zimbabwe, where drought has badly affected the southern region and where cereal output remains 40% below average, leaving millions of people at risk of severe hunger.

But despite poor economic conditions, devastating weather cycles and political instability across the region, WFP warns the HIV/Aids pandemic is the single biggest factor which is undermining recovery.

Because productivity in the agricultural sector is the hardest hit by the spread of Aids, the agency warns food shortages are likely to persist.

James Morris, the agency's executive director, says unless people are well fed they will have no strength to fight the effects of the disease.

"The use of antiretroviral medicine cannot be effective unless the person has good nutrition and has an adequate food supply, and if they're infected and if they're going to resist tuberculosis and polio and malaria and cholera, they have to have good nutrition," Mr Morris said

"Food is the most important drug or medicine or ingredient in the fight against HIV/Aids".