Vietnamese Prime Minister Nguyen Tan Dung has said that his government is considering imposing a duty on rice exports to help ensure domestic food supplies.

He didn't give any details about the duty but said the authorities will act swiftly to ensure adequate domestic food supply and to prevent speculation.

Vietnam, which has a 2008 rice export quota of 3.5 million-4.0 million MT, doesn't currently impose a duty on rice exports. The country's is the world's second-largest rice exporter after Thailand.