Manila: Twenty people, including children, were killed Tuesday in the southern Philippines when the flatbed truck they were riding in plummeted into a ravine, police said.

The vehicle was bringing a group of people home from a trip to the beach when the driver lost control near the town of T'boli in the latest deadly crash on the nation's dangerous roads.

"Based on eyewitness accounts, the truck lost its brakes. We will conduct further investigations on the actual cause," T'boli town police investigator George Tabayan told AFP.

Police initially put the death toll at 15, but doctors said five of the 19 people taken to hospital for treatment later died, Tabayan said, updating an earlier tally.

The dead included children aged between one to six years old, with the driver among those injured, he added.

The group had come from a swimming party at a beach in a neighbouring town and were on their way home when the accident occurred.

Deadly road accidents are common in the Philippines, where inadequately maintained buses and poorly trained drivers form the backbone of land transport options.

In June, 13 people including a bride-to-be were killed when the truck they were riding on after attending a traditional pre-wedding ceremony rolled over on a mountain road.