The suspects were arrested late Saturday aboard a tugboat near Kuala Lumpur, according to Romli Mustafa, a district operations chief of the Malaysian Maritime Enfrocement Agency.
An Afghan national and the vessel's two Indonesian crew were also apprehended in the operation, Romli said.
Romli said it was the first time a large number of Bangladeshi migrants were arrested attempting to enter illegally into Malaysia.
Initial investigation showed they had come via Indonesia, he said.