Mangonui's Chief Fire Officer Ant Pederson suspected that there would be little chance of saving a two-storey house on Pariri Road, Oruru, even before he reached the scene on Sunday night.
The glow from the flames lit up the whole valley, he said, and firefighters had no show of bringing it under control.
The alarm was raised by the tenants at 9.45pm, Mr Pederson saying an exploding solar panel battery had added to the inferno. The cause was initially suspected to involve a generator, although that had not been confirmed by fire investigators yesterday afternoon.
The Mangonui Fire Brigade dispatched two appliances and its water tanker, with Kaitaia sending a third appliance, crews pumping 47,000 litres of water on to the blaze. Much of that water had to be pumped to the scene from a farm dam.
The Northland Age understands that the owner of the house, which was not insured, was overseas.
The Mangonui firefighters did not leave the scene until around 2.30 yesterday morning, and needed another hour to clean up before they were called back at 6.30am, when people at the scene reported that the remains appeared likely to reignite.