Rice prices are heading for higher volatility unless protectionism over the grain is rolled back and output increased, potentially by turning South America and Africa into big producers, academics have warned.

Restrictions on rice shipments imposed following last year's rise in prices threatened to reverse a 50% rise in trading volumes and, in the main, "high degree of price stability" which had characterised the last decade, the International Rice Research Institute said.

The "likely" downturn in trade, with the US forecasting an 8% dip in shipments this year, was a recipe for price spikes and hunger.

"All this points to the risk of making shortages and high prices more frequent," the IRRI said.

"Further protection can be severely damaging for the food security of millions of people."

Tropical expansion

Longer-term, one way to stabilise the market would be to rebuild large stockpiles in major producing countries, and in particular India and China.

"[This] could be expensive but worth considering to have a calming effect," the institute said.

Another option would be to encourage rice growing outside the Asian countries – Thailand, Vietnam, India and Pakistan – which account for 70% of international trade.

"South America has the land mass to expand rice production if the underlying economics make sense," the institute said.

"Africa probably has more potential because of its underused land and water resources. But Africa requires a stable political environment."