ROME - A UN summit on the plight of the planet's one billion hungry opens here Monday, with activists warning it risks being a waste of time as leaders of the world's wealthiest nations are to be conspicuous by their absence.

Italian Prime Minister Silvio Berlusconi is the only leader from the Group of Eight industrialised countries expected to be among the 60 heads of state and government who attend the "Hunger Summit" that runs through Wednesday.

Pope Benedict XVI will be among the inaugural speakers at the meeting at the Rome headquarters of the Food and Agriculture Organisation.

Also expected at the summit are Brazilian President Luiz Inacio Lula da Silva, Moamer Kadhafi of Libya, Egypt's Hosni Mubarak, Venezuela's Hugo Chavez and Zimbabwe's Robert Mugabe.

Humanitarian groups warned last week that the summit could be a "waste of time," calling for the commitment of new resources to fight hunger.

"It's a tragedy that the world leaders are not going to attend the summit," said Daniel Berman of Doctors Without Borders (Medecins sans Frontieres - MSF).

A draft declaration already circulating ahead of the meeting is "just a rehash of old platitudes," said Francisco Sarmento, ActionAid's food rights coordinator.

"Rich countries are failing to show enough interest and urgency," said Oxfam spokesman Frederic Mousseau.

"At the G8 in Italy this summer they pledged 20 billion dollars (S$27.77 billion) for agriculture over three years, so they believe they have done enough. They haven't - and the 20 billion dollars is a mirage," he said.

Even the Italian Catholic Church warned of a possible "flop" unless the summit produces concrete commitments.

The Italian bishops' newspaper Avvenire lamented that the draft final declaration makes no mention of the 44 billion dollars per year that FAO chief Jacques Diouf is seeking for agriculture in poor countries.

"Every six seconds a child dies of hunger," Diouf said last week. "This enormous tragedy is not only a moral outrage and an economic absurdity, but also it presents a serious threat to our collective peace and security."

UN Secretary General Ban Ki-moon will prod world leaders to step up the fight against global warming as well as hunger during his stop at the summit.

"Given the close interrelationship between food security and climate change, the secretary-general will engage world leaders to advance both agendas together," a spokeswoman said last week.

Agricultural production must increase 70 percent if the world is to feed the population of nine billion by 2050, according to the FAO.

Non-governmental organisations plan a parallel forum with the slogan "People's Food Sovereignty Now!" to be attended by Diouf and Rome Mayor Gianni Alemanno.

As delegates gathered Sunday in Rome, the Islamic Development Bank (IDB) made an early pledge of one billion dollars for joint projects with the FAO, the UN agency said.

More than 400 delegates from around 70 countries will attend the forum.