More than 60 people died and thousands were displaced last month when South Africans struggling to feed their families took their anger out on mainly Zimbabwean and Mozambican migrants, whom they blame for rising crime and accuse of "stealing" jobs.

Speaking at the World Economic Forum for Africa in Cape Town, the African National Congress leader said: "This issue of food prices is like a time-bomb. Those who are poor could end up cut out from buying food."

"We are sitting with a situation in which an uprising could emerge ... Those who are poor do not have the luxury of sitting like this and rationalise about what's happening." he said.

Zuma said governments were powerless to control higher food prices and a global solution was needed.

"I don't think there's a lot that governments could do because they are not in control of those who control the rising prices," he said.

Delegates at the forum said millions in Africa were at risk of malnutrition and starvation as food prices were expected to remain elevated over the next few years.

The cost of major food commodities has doubled over the last couple of years, with rice, corn and wheat at record highs. The Organisation for Economic Cooperation and Development sees prices retreating from their peaks but still up to 50 percent higher in the coming decade.

Sheila Sisulu, Deputy Executive Director of the U.N.'s World Food Programme said targeted support for subsistence farmers was needed to help the continent in the short-term.

A U.N. summit on the global food crisis held in Rome on Wednesday asked rich nations to help revolutionise farming in Africa and the developing world to produce more food for the nearly 1 billion people facing hunger.