Former Australian prime minister Kevin Rudd on Thursday criticised the UN food agency for failing to do enough on food security, as fears mount of a repeat of the 2007-2008 food crisis.

Rudd told a conference in Hong Kong that the leadership of the United Nation's Food and Agriculture Organization (FAO), based in Rome, needed to get its act together and not just release "another set of reports".

"The fact that we're having this kind of conference is an indictment of the failure of the FAO," he told the meeting -- titled "Feeding the world: Asia's Prospect of Plenty" -- which was organised by The Economist magazine.

"The execution of its mandate, which is food security, must now be done.

"A practical programme against the billions of people who are hungry in the world today needs to be done -- not another set of reports, not another set of committees. Action, action, action," he told reporters later.

The FAO has called for "swift, coordinated international action" this month as a sharp rise in maize, wheat and soybean prices renews fears of a looming food crisis.

Drought in the United States has pushed grain prices to record highs, and the FAO has cut its global 2012 rice output forecast due to low monsoon rainfall in India.

UN estimates say the world population is projected to increase by two billion people between 2012 and 2050 to around nine billion, with Asia accounting for more than half of the increase.

"Hunger is the world's most challenging problem," UN World Food Programme China director Brett Rierson said.

"There is a common perception that hunger is an African problem, but two-thirds of them are from Asia so hunger is here in Asia," he said.

Manila-based Asian Development Bank warned in April that food shortages could slow poverty reduction, and a rise of 10 percent in domestic food prices could push 64 million more Asians into poverty.