ROME, June 11 -- Britain criticized a United Nations world food summit meeting here today as a waste of time and said the United Nations agency that called it would have to improve its performance if it was serious about reducing global hunger. "I'm not sending a minister because I don't expect it to be an effective summit," Clare Short, Britain's international development secretary, said in criticizing the United Nations Food and Agriculture Organization. "It's an old-fashioned U.N. organization and it needs improvement," she said in an interview with BBC radio in London today, the second day of the four-day meeting. The criticism followed expressions of concern by the United Nations officials who planned the meeting this week over the failure of top world leaders to attend. The meeting was called to urge governments to honor a 1996 pledge to halve hunger in the world by 2015. While dozens of leaders from the developing world have poured into Rome for the conference, most wealthy Western countries sent only their agriculture ministers. Britain did not even do that, dispatching only a junior official. United Nations officials said Western powers did not send top-level delegations because they were indifferent to the hunger issue. The Food and Agricultural Organization hopes the Rome gathering will encourage wealthy nations to open their purses and work harder to cut the number of hungry people to 400 million by 2015, from about 800 million now. Delegates renewed their 1996 pledge on Monday, but failed to resolve long-standing differences over how to go about it, with developing countries accusing rich nations of damaging world agriculture by using subsidies to protect their own farmers. Today, James T. Morris, director of the World Food Program, a United Nations aid agency, urged leaders to stop talking about hunger and start fighting it, warning that up to 13 million people risked starvation in southern Africa unless they received emergency food aid. "This crisis, coinciding as it does with the summit, challenges us right now to demonstrate to those suffering across the region that we will not forget them," Mr. Morris said. The World Food Program says that a mix of drought, poor government and AIDS has caused havoc with harvests in six African countries. "This is the largest single food crisis in the world today," Mr. Morris said at a news conference. He added that the best and cheapest way of tackling global hunger was to focus on the estimated 300 million children who go to bed each night underfed. "We can feed a child in school for 19 U.S. cents a day," he said. "For a very small investment we can change a child's life." Ms. Short said that if the Food and Agricultural Organization improved food management in developing nations, the hunger problem would ease, arguing that many hungry people live in countries that have enough food to feed all their population. "The F.A.O. needs to tighten up its act," she said. The results of the Rome summit meeting will contribute to the agenda of the world summit on sustainable development in Johannesburg from Aug. 26 to Sept. 4. The failure of ministers last week to agree to a draft action plan for the meeting in South Africa only added to skepticism over such meetings, where actions rarely seem to live up to the ideals.: