A volunteer firefighter pulled a man from a room engulfed in flames as a fierce blaze early this morning razed one home and left only a blackened shell of the next door house at Blacks Point, near Reefton.
About 4.50am a house erupted in flames so intense that a neighbour said it sounded like gunshots.
A 42-year-old man was rescued just before the flames jumped to the neighbouring unoccupied house owned by a Christchurch couple.
Reefton Volunteer Fire Brigade station officer Jason Archer was the first on the scene, and by then the second house was already "going up".
The neighbour told him someone was living in the first house.
"I got the boys to give me some protection," Mr Archer said. He jumped the fence, forced his way into the burning house and found a man inside suffering from smoke inhalation.
Mr Archer pulled him out the front door and over the fence, where he was given medical aid.
He said by the time he reached the man the fire "was starting to roll through" the room.
The man was barefooted and had burns on his hands and feet.
They had not long been out when the second house, which had been smouldering, fully ignited in what Mr Archer called a "flash". The roof then collapsed.
Fire safety officers were due on the scene later today and firefighters were expected to remain dampening down the ruins.
With the nearby Inangahua River running low, firefighters used the Ikamatua Fire Brigade's water tanker.
Victoria Miller, who lives close by, was woken by the fire siren, which she does not normally hear at Blacks Point.
She then heard "what sounded like gunshots".
She could see the flames over the large trees in front of her property and, with the area tinder dry, she was initially concerned the fire could spread even further.
"I got dressed and went down, and got there just as the fire brigade arrived."
Constable Mark Watson of Reefton police said they did not know the cause of the fire yet.