Philippine authorities on Saturday raised to 31 the death toll from a passenger ferry that collided with a merchant ship and sank in the central Philippine region, while 172 people remain missing.

The MV St. Thomas Aquinas ferryboat took just 10 minutes to sink after crashing into the MV Sulpicio Express freighter at around 1 kilometer (2/3 of a mile) off the coast of Cebu province, according to GMA television.

The St. Thomas Aquinas, in service for 40 years and with a capacity for more than 900 people, was carrying a total of 830 - 116 crew members and 700 passengers including women and children.

The merchant ship, headed for the province of Davao, came away with a damaged hull but with none of its 36 crew members injured.

Fishermen were the first to arrive and help the victims, who scarcely had time to evacuate the ferry before it went under, though some 629 are estimated to have been rescued, of whom 69 are being treated at local hospitals, chiefly for fractures and traumas.

Emergency management services continue the rescue work, which had to be suspended in the morning due to rough seas, though little hope remains of finding additional survivors.

The St. Thomas Aquinas, coming from the city of Surigao in the southern part of the archipelago, was to call in at Cebu before continuing on to Manila.

Dozens of people die in the Philippines each year in accidents at sea caused by bad weather, failure to comply with safety regulations, poor vessel maintenance and overloading. EFE