Between $15 billion and $20 billion will be needed each year to increase food production to tackle the growing global food crisis, the head of the United Nations said Wednesday.

UN Secretary General Ban Ki-moon, speaking to reporters at an international food summit in Rome, said much of that cash would come from nations working to avert the crisis in food costs and supplies.

Funds must also come from the World Bank, the International Monetary Fund, the World Trade Organization and development banks, he said.

"We must make the international trade system work more effectively to make more food available, at reasonable prices," and boost harvests next year through the urgent supply of seeds and fertilizer, the Ban, who has received a petition with more than 300,000 names, demanding that the world body take action.

UN Secretary General Ban Ki-moon, addressing a UN food crisis summit in Rome, said Wednesday the trade system must work more effectively to make more food available. (Chris Helgren/Associated Press)

Hosted by the UN Food and Agriculture Organization, the three-day summit aims to develop strategies to halt skyrocketing food prices, which have risen an average of 40 per cent worldwide since mid-2007 and 83 per cent in the past three years.

"This is not rocket science," said John Holmes, the UN's humanitarian affairs chief, who is co-ordinating a special task force on the food crisis.

"We know what to do, now we just need to do it."

The group, which includes more than 40 heads of state, will also come up with a final declaration by the summit's close on Thursday.

Canada on hot seat

Canada has come under fire for not sending Prime Minister Stephen Harper or any government member to the summit, choosing instead to be represented by Canada's ambassador to Italy.

"In a hall full of presidents and prime ministers, we've got the local ambassador here," said Pat Mooney, executive director of ETC group and a participant at the summit.

"As a major superpower in terms of food, as a major food exporter, as a food producer, it's not a good sign that we've withdrawn from this debate really, that we're not playing our role as a member of the G8 and try to help solve the problems here."

He said Canada's lack of high-level representation at the summit had put a dent in its stature there and was an "insult to the world community."

Canada, however, has been praised by the head of the UN World Food Program for recently coming forward with emergency funds. In April, Canada pledged an extra $50 million to help the global food shortage this year.

Biofuel debate

On Wednesday, Ban also called for policy guidelines on biofuel production, which has come under fire during the summit for diverting dwindling food crops towards energy production.

While proponents say making fuels from corn, sugar and other organic material could help ease rising oil prices, others say it uses up precious crops that could feed people or animals

The divisive debate means the summit will likely not come to an agreement on the role of biofuels, U.S. Agriculture Secretary Ed Schafer said Tuesday.

Ban said more research on the issue was needed.

A combination of high oil prices, urbanization, the production of biofuels, flawed trade policies and other factors such as climate change have sent food prices soaring, leading to riots and protests in places like Haiti and Egypt in recent months.

An estimated 850 million people globally suffer from hunger, according to the FAO, most of them in developing countries.

With files from the Associated Press