Kuala Lumpur: Dozens of Rohingya are believed to have died during a four-month boat journey to Malaysia, a coastguard official said Wednesday.
There had been more than 300 people on board the boat which was intercepted by authorities earlier this month, said Zubil Mat Som, director-general of the Malaysian Maritime Enforcement Agency.
The 269 survivors were taken to Langkawi island.
"Some of them died at sea. They were thrown overboard," Zubil told reporters, without specifiying the exact number.
Zubil said the group had been on a "motherboat" carrying more than 800 people before being transferred to a second vessel.
Authorities have not found the original boat thought to be now carrying around 500 people.
"We cannot locate them," he said.
Malaysia is a favoured destination for Muslim Rohingya fleeing violence in mostly Buddhist Myanmar, with thousands trying a perilous escape via smugglers across the sea every year.
Rohingya usually travel either from Myanmar or Bangladesh, where about one million live in squalid refugee camps. Most of those fled a 2017 military crackdown in Myanmar.
Fears have been growing in recent months that large numbers of the migrants are trapped at sea as countries that traditionally allowed them in turn their boats away.
Malaysian authorities have strengthened maritime patrols to prevent illegal entry by foreigners over fears they could be carrying the coronavirus.
Malaysia has vowed to send the latest arrivals back to Bangladesh.