A boat crammed with scores of Rohingya migrants, including many young children, was found drifting in Thai waters yesterday, with passengers telling AFP that at least 10 fellow boatpeople had died over the past few days.

Dozens of visibly weak-looking people were on the deck of the stricken vessel, which was found adrift several kilometres off the southern Thai island of Koh Lipe, in the Andaman Sea, according to AFP correspondents at the scene.

"About 10 people died during the journey. We threw their bodies into the water," one migrant shouted in Rohingya to a boat carrying reporters.

"There are 300 of us... we have been at sea for two months. We want to go to Malaysia but we have not reached there yet."

A group of women wearing headscarves who were huddled on the deck cried as reporters approached, one AFP correspondent said, many with young children and toddlers in their arms.

Women cry as they look for help. Photo: AFP

"My children are sick and we haven't had anything to eat for a week," a mother of four who gave her first name as Sajida shouted out.

The words "We are Myanmar Rohingya" were daubed in English on a black flag tethered to the wooden boat, while a large tarpaulin had been erected to protect the stricken and weak migrants from the blazing tropical sun.

Initially there was no immediate sign of Thai authorities who have apparently been scouring the area for a number of vessels laden with migrants adrift in the area.

Eventually a Thai Navy helicopter dropped food packages into the sea and was later joined by other boats.

Desperate scenes followed as several emaciated men jumped into the sea to retrieve the packages, one of them eating handfuls of raw instant noodles in the water before swimming back to the boat.

Rights groups fear hundreds, possibly thousands, of Rohingya have been cast adrift on rickety boats in the Andaman Sea in recent days, abandoned by smuggling gangs spooked by a belated crackdown on the thriving people-smuggling trade in southern Thailand.

Both the UN's refugee agency and the International Organization for Migration have called for a coordinated search and rescue effort, something regional nations have so far resisted.

Instead Malaysia and Indonesia have vowed to bar boats bearing desperate migrants from Myanmar and Bangladesh after nearly 2,000 boatpeople were rescued or swum to shore earlier this week.

People pass food supplies dropped by Thai army to others. Photo: AFP

A Malaysian official, speaking on condition on anonymity, yesterday told AFP that two vessels carrying a combined 600 migrants had been turned away.

Thailand has long practised a policy of encouraging migrants to continue their journeys towards Malaysia.

"They want to go to Malaysia but the ship has no engine, it was scuttled by their broker," Navy Lieutenant Commander Veerapong Nakprasit said, referring to the latest vessel. "We will send a technician to fix the engine so they can go to their destination."

Major General Sunsern Kaewkumnerd, a junta spokesman, said Prime Minister Chan-O-Cha had been made aware of the boat.

He said Thailand was willing to provide humanitarian assistance but if the migrants aim for Thailand they will be treated as "illegal immigrants".

"The refugees want to go to a third country," he said, adding that Navy officials expected the engine to be fixed later yesterday.

Thailand has launched a crackdown to disrupt people smuggler networks since the discovery of dozens of bodies in abandoned camps along regular trafficking routes.

As many as 8,000 migrants from Bangladesh and Myanmar are believed by the International Organisation for Migration (IOM) to be stranded at sea.

Men depicts their miseries as the journos approached them. Photo: AFP

People smugglers are reportedly refusing to land their boats because they do not want to follow their usual route through Thailand since the government's campaign against them began.

A senior Thai official told Reuters news agency on Wednesday that Thailand, Malaysia and Indonesia would all continue to turn the boats away.