A reduced maize surplus, because of poor rains, could lead to an increase in food prices, the Business Day reported on Friday.
"Last year we had a super year as rains were great, but this year is a bit dry," Grain SA chief executive Jannie de Villiers told the newspaper.
Grain SA predicted that the country's maize surplus would be a million tons -- a quarter of that last year.
Crop yields were also expected to be lower in the United States and China, and global demand could put pressure on food prices.
South African farmers had allocated more land for maize, hoping to capitalise on high international prices, but the yield per hectare was expected to be lower than last year, Grain SA said.
De Villiers forecast a crop of 11 million tons for 2012. Of this, a million tons was allocated for export.
National Agriculture Marketing Council CEO Ronald Ramabulane said it would be known whether grain reserves would negate food price increases when new data on maize and grain stock was released in two weeks.