"The driver lost his brake and lost control," Stephen Polinar, spokesperson of Negros Oriental's provincial police office, told DWPM radio station. "It was raining for two days so the road was slippery."
Rescuers rushed to the accident area on Wednesday afternoon, and all passengers were already accounted for, Polinar said.
The driver is being treated at a hospital and could face charges, he added.
The Philippines is notorious for its lax regulation on public transportation, including passenger overloading, and poorly maintained roads.
In December, 17 people died when a bus lost its brakes and plunged into a ravine in the central Philippines province of Antique.
(Reporting by Neil Jerome Morales; Editing by Chris Reese)
