The fire that destroyed an empty house in Ohakune in the early hours of Sunday morning appears to have been deliberately lit, specialist fire investigator John Hotter says.
He attended the scene later that morning and said the neighbouring houses nearly went up too.
Fire crews from Ohakune and Raetihi found the Miro St house "pretty much destroyed" when they arrived about 2am.
They turned their attention to damping down surrounding houses.
Windows broke and wood was charred on one of those. Most were holiday homes, but one had two people inside.
It was good the fire crews arrived when they did, Mr Hotter said. "Any later and there would have been two or three houses on fire."
Police are investigating the fire.
Anyone with information can ring (06) 385 0100 and ask for Ohakune Police, or give information anonymously via Crimestoppers on 0800 555 111.