In Vietnam, 5% broken rice rates fell to $340-$350 a tonne on Thursday from $350 last week.

"We've heard the Philippines will likely ban imports during its harvest in September to support local farmers," a trader in Ho Chi Minh City said.

Buyers in the Philippines, one of Vietnam's top buyers, had bought a lot of rice recently to build inventories, another trader said.

Thailand's 5-percent broken rice prices rose to $395-$405 a tonne, free-on-board Bangkok (FOB), from $390-$395 last week mainly due to a widespread drought while overseas demand remained flat, traders said.

"The drought is raising concern about a possible supply shortage," a Bangkok-based trader said.

High prices for Thai rice and a strong baht could deter buyers, traders said.

"There are no major deals in sight," another trader said.

"All we've had so far this year are small deals with regular customers and that's not really affected prices as much as the currency exchange and supply situation."

The world's second-largest rice exporter has seen a 19.6 percent decline in exports between January and June versus the same period last year, according to the Thai Rice Exporters Association.

Adverse weather hit markets in Bangladesh as well, with flooding submerging more than 100,000 hectares of paddy, according to a preliminary assessment by the agriculture ministry.

This comes at a time when farmers are struggling to secure fair prices for produce, with no overseas deals in sight since the country lifted an export ban in May, traders said.

Agriculture minister Abdur Razzaque said the government would reduce fertilizer prices and provide modern equipment to growers to reduce costs.

Bangladesh's central bank instructed authorities not to reclaim previous loans and provide fresh ones to help flood-affected farmers.

In India, prices of 5 percent broken parboiled rice were unchanged around $381-$384 per tonne.

"Demand from buyers in Africa is not improving. They have bought enough old stocks from China at lower prices," said an exporter based at Kakinada in the southern state of Andhra Pradesh.

India's exports could fall to a seven-year low, officials said.

Meanwhile, farmers planted paddy on 18.5 million hectares as on July 26, versus 19.8 million hectares during the same time last year, while forecasts for an improvement in monsoon rains assuaged drought fears and lifted expectations for a robust yield of summer crops such as rice.