The "Aung Takon 3" sank late March 13 after leaving the coastal town of Kyaukphyu on its way to Sittwe in western Rakhine state.
"We found 18 more bodies today and the search is still continuing," U Kyaw Thura, a police official in Kyaukphyu, told AFP, adding that the total death toll now stood at 52.
Myanmar state media on March 16 said the ferry was carrying 218 passengers and crew when it sank.
But locals have said they fear far more unregistered ticket-holders may have been on board, a common practice on the impoverished nation's often overcrowded ferry network.
Many Myanmar citizens living along the country's lengthy coastline and flood-prone river systems rely on poorly maintained ferries for transportation.
The area where the "Aung Takon 3" capsized is notorious for its treacherous waters.
Rakhine state has also become the departure point for thousands of desperate Muslim Rohingya, who crowd onto small and dangerously overcrowded boats to escape persecution, often aiming for Thailand and Malaysia.
Many of the barely seaworthy boats never reach their destinations.