LOS BANOS (Philippines), Mar 19 (AFP): As the price of rice hovers near record levels, many poor countries face the spectre of riots by hungry people, according to one of the world's leading rice experts.

Key producers India and Vietnam have both curtailed exports, sending some of the world's largest rice importers including the Philippines scrambling to procure supplies for their people.

Spot prices have recently hit more than 700 dollars a tonne, more than three times the price of just five years to go.

Industry officials in Thailand, the world's top exporter, have warned that prices could soon rise to 1,000 dollars a tonne.

Vietnam, the world's third-largest exporter of the grain, also faces the prospect of a return of the deadly crop disease that impacted heavily on its crop yield last year.

These are just some of the problems that keep Robert Zeigler, head of the International Rice Research Institute (IRRI) up late at night.

Located at Los Banos, a university town south of Manila, IRRI is regarded as the one of the world's premier centres for rice research.

Looking out across paddy fields from his office, Zeigler quoted a Latin American saying: "When the price of rice rises, governments fall."

"If people don't have enough to eat and they don't have enough money to buy enough to eat, that translates frequently into social unrest," he told AFP in an interview.