One patient was assessed at the scene and was being transported to Wellington Hospital in a critical condition by helicopter.
Smoke and flames from the house fire could be seen from much of the Bay View township, but had largely dissipated by 3pm.
A worker in the Bay View township, who did not want to be named, said he heard five or six fire engines screaming past.
He went outside and saw the building completely covered in flames.
“It was terrible,” he said. “It was completely gone … I don’t think there will be anything left.”