A battery-powered hoverboard has been blamed for a fire that damaged a child's bedroom at a house in Kaitaia on Sunday night.
A Kaitaia Fire Brigade spokesman said the damage would likely have been much worse but for the residents' quick response.
The fire was well away when it was discovered. The residents closed the door and fought the flames with a garden hose through a window until the brigade arrived.
"They did everything right, and the fire was contained to that room," Station Officer Ross Beddows said.
The source was found to be a hoverboard that was leaning against a wall just inside the door. Mr Beddows said it had been used by its 13-year-old owner a few hours earlier and had self-ignited, setting fire to the wall, carpet and the duvet.
Sufficient heat was generated to melt electrical equipment on the other side of the room.
"It was extremely fortunate that the fire started early in the evening, when the occupants were still awake," he added.
"If it had been the middle of the night when they were asleep it may well have proved deadly."
The owner's grandfather, who did not wish to be named, said the teenager and her mother saw flames through one of the windows when they returned to the house from fetching takeaways at around 9.15pm.
He confirmed that the house did have a smoke alarm, but the battery had died.
His granddaughter had owned the board for two years, and had taken it with her when the family flew to Dunedin last Christmas, although the airline had been reluctant to take it.
Airlines have since adopted a common policy of refusing to carry them because of their propensity for spontaneously catching fire.
Meanwhile deputy Chief Fire Officer Craig Rogers said the two appliances that responded to the fire had difficulty reaching the house thanks to trees on the neighbouring property overhanging the driveway.
Trees and other vegetation commonly made access to fires difficult, and were becoming an increasingly worrying issue.