A family was lucky to escape a burning house in south Auckland after a smoke detector gave them an early warning.
A seven-year-old girl is being treated for serious burns to up to half of her body.
The acrid fumes still hung in the air on Wednesday morning as police and fire investigators worked to find out what happened.
Emergency services were called when smoke began billowing from this Mangere East home on Tuesday evening, with up to six people still inside.
Witnesses watched on in horror.
"There was just a trail of black smoke going into the air," said Valerie Teraitua, manager of the Papatūānuku Kōkiri Marae.
"So I walked up and then I witnessed a little girl getting hosed down with cold water."
The injured girl, a twin, is understood to have run from the house screaming and on fire.
The man who helped hose her down was an off-duty firefighter passing by. She's in hospital being treated for serious burns.
Fire investigators says there was a disabled teenager among those home at the time and his father carried him out to safety, but by the time he returned to tackle the flames it had already got out of control.
The fire destroyed a bedroom in the Housing New Zealand home. It's policy for them to have smoke detectors, and in this case, investigators say it probably saved lives.