The rising cost of food was a time bomb that could result in uprisings, ANC president Jacob Zuma told the World Economic Forum on Africa on Thursday.

"The issue of food prices is actually a time bomb," he told a plenary of the forum, being held in Cape Town.

"With those who have the budgets to adjust, [it] is one thing. But with those who have no money to buy at all, once the food price goes up, they are cut out, even from the possibility of buying food.

"Then you are sitting with a situation that an uprising would emerge." Escalating cost of wheat

Zuma was speaking against the background of a global doubling in the price of wheat in the past year, and an almost 80 percent hike in the African and Asian staples maize and rice over the same period.

Soaring food costs have already sparked riots in Egypt, Indonesia, Cameroon, Peru and Haiti.

United Nations Secretary General Ban Ki-moon warned this week that food production had to rise by 50 per cent by the year 2030 to meet the rising demand.

Zuma told the WEF meeting he did not think there was a lot that governments could do about the issue, and that politicians were being asked to solve problems beyond their control.

"We must have global solutions to global problems... a multilateral approach to identify where the problems begin and what then must be done," he said.

Finance Minister Trevor Manuel, speaking at the same plenary, said that in addressing the problem there was a need to focus on governance broadly, and multilateralism was an important part of this.

"But part of what we don't want to talk about is what lies upstream from agriculture, and one of the issues upstream is clearly the oil price," he said.

He said that in South Africa about 34 percent of the price of a loaf of bread emanated from the wheat price and 36 percent from the logistics chain. The oil price factor

Oil prices were driving up food prices, and if that was not changed, they would continue to soar.

Manuel warned that governments should not allow themselves to be dragooned into taking short-term decisions.

"We need to ensure there is support for agriculture, but we must guard against the introduction of subsidies that become an end in itself," he said.

He said the 50 percent call by Ban was "interesting" but did not know whether the goal was reachable.

Unlocking Africa's potential meant more than just buying fertiliser: it also meant establishing infrastructure such as roads, water harvesting, and storage capacity.

All of this required a measure of government support, which could be done in the short-term.

Manuel also said governments should take a stand on "demand management".

"You know, in the United States, every individual consumes the equivalent of 40 kilograms of chicken at the moment. In 1980 it was 20 kilograms per year.

"That kind of demand is unsustainable because we are dependent on factors of production like soil and climate, over which we have no control.

"Governments must be involved in communication on demand management, failing which I think the wealthy are going to take everything leaving the poor destitute."

Sapa