Rough seas on Friday forced Philippines rescuers to suspend the search for dozens of people still missing a day after a ferry disaster claimed at least 38 lives.

The Kim Nirvana, believed to be carrying 189 passengers and crew, capsized off a central Philippine port on Thursday shortly after setting sail from Ormoc city for its regular run to the Camotes island group, about an hour's sailing away.

Distraught relatives waited at the Ormoc city port on Friday for news of the missing, after a sleepless nighttime vigil, while others checked hospitals and morgues for their loved ones.

At the port, 10-year-old Gilbert de la Cruz kept his eyes fixed on the partially submerged wooden hull where his mother, eight-year-old sister and one-year-old brother were believed trapped.

"I'm very sad because I don't know if they are still alive," said the boy, who survived the accident by clinging to empty water drums that kept him afloat until the coast guard rescued him.

"I am never riding a boat again," he told AFP, as he was comforted by his aunt whose eyes were swollen from crying.

The authorities have said they are puzzled as to how the accident happened in relatively calm waters, but discounted speculation that the ferry was overloaded.

Survivors have recounted how the 33-tonne vessel was backing out of the port when it suddenly overturned, giving them no chance to put on life jackets.

Coast guard and navy rubber dinghies circled the hull Friday, but no survivors have been found since Thursday afternoon. Local officials have said that 125 people have been rescued, leaving 26 unaccounted for.

Divers stopped their search as the seawaters became turbulent, and the seabed grew murky due to bad weather from Tropical Storm Linfa, said Chief Superintendent Asher Dolina, the police commander overseeing the operation.

- 'Miracles can happen' -

Linfa was set to brush past the northern Philippines later Friday.

"The waves are big and it's dangerous for our divers. The water is also silted, almost zero visibility," Dolina told AFP.

Asked if rescuers still expected to find survivors, he said: "We really can't say. Miracles can happen."

Dolina said the search would resume when the weather improved.

The state weather service issued a gale alert for the central Philippines early Friday, warning of turbulent seas being churned up by the storm.

Waves up to 4.5 metres (about 15 feet) high could overturn boats that try to leave the ports in these conditions, weather forecaster Gladys Saludes told AFP.

Nicasia Degesica, a 57-year-old seamstress, waited at the port for news of her elder sister, Erlinda Rosales.

"We're losing hope that she is still alive, but if she's dead at least we want to find her body," Degesica told AFP.

Poorly maintained, loosely regulated ferries are the backbone of maritime travel in the sprawling archipelago of 100 million people.

The boats have had frequent accidents in recent years, claiming hundreds of lives, including the world's worst peacetime maritime disaster in 1987 when the Dona Paz ferry collided with an oil tanker, leaving more than 4,300 dead.

Many of the ferry disasters occur during the typhoon season between June and October, when strong winds also unleash deadly floods and landslides.

The disaster-plagued Philippines is hit by about 20 typhoons and storms each year, many of them deadly.