Mr Ban, who will lead the task force, said he agreed with UN agency chiefs on a series of measures for the medium and long term, with the first priority meeting the US$755 million (S$1 billion) shortfall in funding for the World Food Programme (WFP).

'We anticipate that additional funding will be required,' he told reporters in the Swiss capital Bern where the UN agency chiefs have been meeting.

But he said more was needed to provide for future needs. 'We must ensure food for tomorrow,' he said.

Mr Ban said there were a number of causes of the food crisis including climate change, long spells of drought, changing consumption patterns in major developing countries and the planting of crops for biofuel.

He said new measures had to go farther than just providing emergency food relief when crises hit unlike the previous global response.

The UN's Food and Agriculture Organisation (FAO) has developed a US$1.7 billion plan to provide seeds for farmers in the world's poorest countries, he said.

'We must make every effort to support those farmers,' Mr Ban said.

He said he hoped world leaders would come to a June meeting in Rome to find ways to tackle the food crisis. He said the international community had previously not listened to warnings from the FAO and others.

'This time the whole United Nations is now leading this campaign to address this issue,' he said.

World Bank President Robert Zoellick also called on Tuesday fpr countries not to ban exports of food, which worsens the problem of rising food prices.

'We are urging countries not to use export bans. These controls encourage hoarding, drive up prices and hurt the poorest people around the world who are struggling to feed themselves,' Mr Zoellick said in a statement.

'The next few weeks are critical for addressing the food crisis,' he said after a meeting of UN agency heads to tackle the food price crisis. He said he believed rice and corn prices would remain high, and wheat relatively high.

Impact of high rice prices

Soaring rice prices have forced the WFP to indefinitely suspend a programme supplying free breakfasts to 450,000 poor Cambodian schoolchildren, an agency official said on Tuesday in Phnom Penh.

'The cost of rice' was the main reason behind the move, Thomas Keusters, WFP country director in Cambodia, said.

Mr Keusters said the agency had suspended the popular programme since last week until mid-July when students go on holiday. The move affects 450,000 children in 1,343 schools countrywide.

He said the programme was suspended because the WFP could not afford to pay the current high prices for rice, which accounts for 76 per cent of the school breakfasts.

Better quality rice now sells for more than 700 dollars per tonne in Cambodia compared with 300 to 400 dollars last year, according to sellers.

Mr Keusters said some schools were using their own rice stocks to feed the children but they would also run out in less than a month.

He said the free breakfasts programme was important to attract children to school and being fed helped them pay attention in their lessons.

WFP introduced free school breakfasts in Cambodia about eight years ago but Mr Keusters said he did not know when or whether the programme would restart. -- AP, REUTERS