The death toll in the Philippines ferry mishap has gone up to 54 while confusion continues on the total number of passengers aboard the vessel.

The MV Kim-Nirvana held 173 passengers and 16 crew members, according to authorities, but the coast guard suspects more were aboard.

There are 142 survivors after the ferry, on a regular trip to Camotes Island, capsized on 2 July near the central port of Ormoc. The 33-tonne boat overturned after being hit by a big wave.

Rescue operations are being widened to the nearby islands and coastal villages in the region, report agencies.

Tropical storm Linfa passing over the archipelago with prediction of turbulent seas has hampered rescue efforts.

Survivors say the vessel was backing out of port when it suddenly overturned, giving them no chance to put on life jackets.

Human error in weathering the stormy waters as also overloading are being considered as possible reasons for the accident.

The south-east Asian nation has seen a string of maritime disasters occurring mostly during the typhoon season.