Seventeen people were killed when a passenger bus careered off a road and plunged down a mountain in the central Philippines, an official said Wednesday. 

The bus was traveling on an "accident-prone" section of road in Hamtic municipality in Antique province when the crash happened Tuesday afternoon, said Roderick Train, head of the provincial disaster agency.

Seven people were in critical condition in hospital and four others were stable, Train told AFP.

"This is a mountain road, so the bus fell from a high place. That's why the impact caused many casualties," Train said.

"This Hamtic-Iloilo road is an accident-prone area and what happened … based on the witnesses, was a mechanical failure. The driver lost control, possible brake failure."

Provincial Governor Rhodora Cadiao visited the hospital where survivors were being treated for their injuries. 

"It's very, very sad," Cadiao said in a video posted on the government's Facebook page. 

Train said the search and rescue operation had finished and authorities would now focus on retrieving the bus. 

"We searched for the bodies until this morning," Train said. "It was tiring to go up and down."

Deadly road accidents are common in the Philippines, where drivers frequently flout the rules and vehicles are often poorly maintained or overloaded.