The bus was carrying dozens of people when its brakes failed in the central province of Antique on Tuesday afternoon, the local governor, Rhodora Cadiao, told a press conference on Wednesday.
Seven people were in critical condition while four were stable and recovering, she said.
Local media had reported earlier than 28 died in the crash.
A passenger bus has plunged 30m off a cliff on a notorious stretch of road in the Philippines. (AP PHOTO)
Cadiao said the bus was travelling to Culasi in Antique from the neighbouring province of Iloilo when its brakes malfunctioned on a winding road and it plunged 30m into the ravine.
"We call that area the killer curve," Cadiao told DZRH radio station.
"It was already the second bus that fell off there."
Rescue operations at the site have stopped after all visible bodies were retrieved, the Antique government said on Facebook.
"The engineering design of this road is very faulty," Cadiao said.
"I want to condemn that road already."
The Philippines is notorious for its lax regulation of public transportation and poorly maintained roads.
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