At least 11 workers were reported injured after a scaffolding at a power plant in Pililia town in Rizal province collapsed Sunday afternoon.
According to GMA News' Twitter account, at least five more workers are feared trapped in the plant's chimney.
Police said they could not talk to the plant's owners, saying security was very tight.
Initial investigation showed the incident occurred at about 1 p.m.
Rescue operations were continued as relatives waited for updates.
Police are still looking into what caused the scaffolding to collapse.