Food crises are jeopardising efforts to achieve the millennium development goal of halving the proportion of people who suffer from hunger by 2015, United Nations food experts warned today.

In an annual report on world hunger, UN food agencies said food price volatility is likely to continue and possibly increase, making poor farmers, consumers and countries more vulnerable to poverty and food insecurity.

"Demand from consumers in rapidly growing economies will increase, the population continues to grow, and further growth in biofuels will place additional demands on the food system," the report said, adding that food price volatility may increase over the next decade due to stronger links between agricultural and energy markets and more frequent extreme weather events.

Small, import-dependent countries, particularly in Africa, are especially at risk, with many of them still facing severe problems following the world food and economic crises of 2006-2008, the UN Food and Agriculture Organisation (FAO), the International Fund for Agricultural Development (Ifad) and the World Food Programme (WFP) said in their joint report.

The report emphasised that investment in agriculture remains critical to sustainable, long-term food security and called for money to be put into irrigation, improved land-management practices and better seeds developed through agricultural research.

With the global population expected to increase from 6.9 billion to 9 billion by 2050, the problem of feeding the world is increasing preoccupying governments. Food security was put on the G20 agenda this year under the group's French presidency.

NGOs point out, however, that developed countries have yet to live up to their pledge to invest $22bn in agriculture development. The money was promised at L'Aquila, Italy in 2009, following food crises that triggered riots in 30 countries across three continents.

The report said predictable policies and openness to trade were more effective strategies for governments than export bans and other restrictive policies, which risk increasing volatility and high prices on international markets, The Guardian reported.