UNITED NATIONS (Reuters) - A food crisis sparked by rising prices risks derailing global efforts to reduce poverty and international action is urgently needed, world leaders and experts told a high-level U.N. meeting on Tuesday.

"Today 25,000 people will die because they did not get enough to eat," British Prime Minister Gordon Brown said in a video message to a special meeting of the U.N. Economic and Social Council on the global food crisis.

Brown pledged to champion the cause of fighting poverty and hunger at an international level, including among the G8 group of industrialized nations that are the main donor countries.

U.N. Deputy Secretary-General Asha-Rose Migiro said that even before the crisis, 830 million people faced acute food shortages, and rising food prices would push another 100 million people or more into deep poverty.

U.N. Secretary-General Ban Ki-moon said last month he was creating a high-level task force to address the food crisis.

Tuesday's meeting was part of that effort to coordinate policies and propose ideas ahead of a food summit in Rome next month.

Migiro said the task force would aim to find ways to meet emergency needs, including a U.N. World Food Program call for an extra $755 million to fund the rising costs of its current operations.

Speakers at the meeting said crucial to overcoming the long-term causes of the crisis is assistance for developing countries to boost local food production by helping small-scale farmers.

Economist and development campaigner Jeffrey Sachs said rich countries held the key to achieving the U.N. Millennium Development Goals, a set of pledges adopted by U.N. member states to sharply reduce poverty and hunger by 2015.

"All hangs in the balance," Sachs said. "The limiting factor is the response of the rich countries, because things can be done, but the finance has not been there. The promises have not been kept," he said.