The Philippine coast guard was searching on Monday for 17 crew of a landing craft that went adrift south of the capital, Manila, one of three weekend accidents at sea, an agency spokesman said.
Sea accidents are frequent in the Philippines, comprised of more than 7,000 islands, with lax regulations, ageing marine vessels and strong waves all contributing.
"Seventeen crew are missing and we are still looking for them," said the spokesman, Captain Armand Balilo, adding that the craft lost power near Fortune Island, a tourist spot in Batangas province.
Elsewhere, authorities on Sunday rescued all 14 boat passengers, mostly tourists, on the holiday island of Palawan and 19 people from a boat in the southeastern province of Camarines Norte, after both crafts capsized in strong waves, the coast guard said.
In December, the Philippines' coast guard rescued 252 passengers and crew, including an Australian and his Philippine wife, and retrieved five bodies from a ferry capsize in bad weather.
Reporting by Neil Jerome Morales