A recent drop in food prices could discourage farmers from sowing crops and cut supplies to an increasingly hungry world, according to the head of the UN Food and Agriculture Organisation.
Speaking in Madrid, FAO chief Jacques Diouf told the high-level meeting on Food Security For All that planting could fall in the next crop year.
"That would entail a significant drop in output in 2009/10 and a sharper increase in prices than in 2007/08, unless it is tempered by the effect of the economic recession on income," Mr Diouf said in an opening speech.
"If to that we add growing demand for produce for bioenergy, it is very likely that determining supply and demand factors will aggravate food insecurity in developing countries."
A report from London-based thinktank Chatham House also saw recent falls in food prices providing only a temporary reprieve with the uptrend set to resume in the medium-to-longer term.
"There is a real risk of a 'food crunch' at some point in the future, which would fall particularly hard on import-dependent countries and on poor people everywhere," the report said.
The report said climate change, water scarcity and competition for land would make it hard to meet an expected 50 per cent rise in demand for food by 2030. It called for more investment in agriculture with a focus on helping small farms.
Aid agency Oxfam, in another report, echoed concerns about the need to invest more heavily in agriculture.
"Decades of underinvestment in agriculture coupled with the increasing threat of climate change mean that despite recent price-falls, future food security is by no means guaranteed, and in fact the situation could get worse," Oxfam said.
Cereal stocks of 431 million tonnes were enough to cover just 19.6 per cent of demand, the lowest level in 30 years. A food security summit held in Rome last year had prompted pledges of €16.5 billion in food aid, which Mr Diouf said was "very encouraging", although at the time he said €22.6 billion a year was needed to boost farm production in poor countries.
The FAO estimates that almost one billion people suffer from malnutrition, a number which rose by 40 million last year.