By Anjana Anil

March 5 (Reuters) - Indian rice export prices edged lower this week on surplus supplies and rupee depreciation, while Vietnamese rates remained unchanged and Thai rates eased, with traders assessing the Middle East supply situation.

India's 5% broken parboiled variety RI-INBKN5-P1 was quoted at $348-$353 per metric ton, compared with the previous week's $350-$356. Indian 5% broken white rice was priced at $346-$351 per metric ton.

"We are passing on the gains from the rupee's fall to overseas buyers, yet demand remains sluggish," said a Kolkata-based dealer. The Indian rupee fell to a record low this week, increasing traders' margins from overseas sales.

About 400,000 tons of Indian basmati rice are backed up at ports and in transit, while export deals have dried up as freight rates have more than doubled since the U.S.-Israel attack on Iran, officials said.

Vietnam's 5% broken rice RI-VNBKN5-P1 was offered at $360-$365 per ton, largely unchanged from the previous week, according to traders.

"Trading activity is weak as buyers are waiting for prices to fall," a Ho Chi Minh City-based trader said, adding that domestic supplies are rising amid the winter-spring harvest.

The Iran war hasn't directly hit rice shipments from Vietnam to Africa, but Africa-bound shipping costs have risen significantly on higher insurance and fuel expenses, traders said.

The U.S.-Israeli war against Iran widened after a U.S. strike hit an Iranian warship off Sri Lanka, deepening a crisis that has paralyzed shipping through the Strait of Hormuz.

Global grains trader Bunge BG.N is exploring alternative shipping routes to minimize disruptions due to the conflict, a company spokesperson told Reuters.

Preliminary shipping data showed over 382,000 tons of rice were loaded at southern Vietnam ports in February, with most heading to the Philippines and Africa.

A Bangkok-based trader said it needs to be seen if the conflict in the Middle East causes hoarding and increases demand.

Thailand's 5% broken rice RI-THBKN5-P1 eased to $380 per ton from $385 the previous week.

Indian rice is undercutting prices, the trader said, adding the El Nino situation could cause production to decline.

Rice prices in Bangladesh have risen again, prompting authorities to order ministries and agencies to take immediate action to curb the increase.

Prices rose despite the government increasing imports, while private traders have also been allowed to import rice.

(Reporting by Anjana Anil in Bengaluru, Khanh Vu in Hanoi, Chayut Setboonsarng in Bangkok, Rajendra Jadhav in Mumbai and Ruma Paul in Dhaka; Editing by Jonathan Ananda)