"There is very little chance of finding those missing alive. Most of them are women and children," said an official in Pathein, the provincial capital.
Marine accidents are common in military-ruled Myanmar, whose 48 million people rely heavily on crowded, old boats for water transport.
People in the remote areas particularly those living in the delta region often travel and transport goods by boat because of the low cost and the lack of access by road to many areas.
In March 2008 about two dozen pilgrims drowned when their overcrowded motorboat sank in central Myanmar.
The Irrawaddy delta region was badly hit by cyclone Nargis in late April 2008, killing more than 150,000 people.