The U.N. Food and Agriculture Organization warned that wheat stocks need to increase by 3.5 percent and maize by 6 percent in 2011 compared with 2010 levels to meet global demands.
Meanwhile, prices have soared passed 2009 levels.
Abdolreza Abbassian, secretary of the international group on grains at the FAO, said growing conditions were expected to be normal for next year but harvests were in a delicate state.
"We are assuming we will have normal growing conditions but if we have heavy rains or drought in some of the cereal-producing countries we could be in trouble, or if we have great growing conditions production could go up by more than expected levels," he told the United Nations' humanitarian news agency IRIN.
Severe drought and raging wildfires that hit Russia and Ukraine this year sent shockwaves through global grain markets. Russian and Ukraine are the two largest grain producers in the world and the disasters caused major price increases as crops were damaged.
"We not only need to replenish our stocks in 2011 but we need to do better than that to ensure we have stocks to last us in 2012," said Abbassian.