On Monday, authorities detained a vessel near Pyapon township, around 120 kilometres south of commercial hub Yangon, said the Global New Light of Myanmar newspaper.
“Four traffickers and 65 smuggled Bengalis were temporarily detained,” it said, using the term by which Rohingya are pejoratively referred to by many in Myanmar.
Three men and four women later “died due to the bad weather and lack of food and water”, it said.
Six others were still receiving medical treatment, while five men from the group “were detained so that they could be investigated and prosecuted under the law”, the newspaper added.
Hundreds of thousands of Rohingya Muslims fled a military crackdown in Buddhist-majority Myanmar in 2017, arriving in neighbouring Bangladesh with harrowing stories of murder, rape and arson.
The Rohingya still in Myanmar are widely seen as interlopers from Bangladesh and are largely denied citizenship, many rights and access to healthcare and education.
Each year, hundreds make perilous, months-long boat journeys to other parts of Southeast Asia, often during the November-March period when the sea is safest for the small trawlers used by traffickers.
Malaysia, a Muslim-majority nation, is the favoured destination as it hosts a sizeable Rohingya diaspora.