At least 33 people were killed after a passenger ferry with 173 on board capsized in rough waters in the central Philippines on Thursday, a disaster monitoring official said.

At least seven rescue boats picked dozens of survivors who clung to the overturned hull of the Kim Nirvana, one kilometre (about half a mile) from Ormoc port, Ciriaco Tolibao from the city's disaster risk reduction and management office told AFP.