He said the fire started in the lounge and was fuelled by furniture.
At midday today he was still "working through, sifting through the debris", he said.
The house on Clinkard Ave was "well involved" when fire crews arrived last night. Photo/Supplied In a statement, a Housing New Zealand spokesman said the house was vacant because it was between tenancies.
"The tenancy ended a few weeks ago and Fire and Emergency NZ is investigating the cause [of the fire]."
Rob Isaac has lived next door for more than 23 years.
He said he was in the far side of his house when neighbours rushed to his door to alert him to the fire.
"I went out and saw a big blaze."
He grabbed a hose and started to spray his fence to keep it cool.
"It was lucky nobody was in there. It took about seven minutes from the first calls for the emergency services to arrive, which I thought was quite fast."
Police investigators at the scene on Clinkard Ave. Photo/Stephen Parker A neighbour across the road from the burnt house said she had been there for 50 years.
The woman, who did not with to be named, said when she saw the fire, the first thing she did was reach for the phone.
"By the time I called 111, they [emergency services] were here."
She said it quickly became clear there was nobody inside.
"People. That's always the first thing through your mind when you see something like that."
Police investigators at the scene on Clinkard Ave. Photo/Stephen Parker The woman said once the fire took hold and windows started smashing, everyone was out of their houses.
"The kids were quite fascinated, they were not scared."
She said she suspected from the beginning that the fire was deliberately lit, and she was "devastated" by the whole thing.
"I don't know why you would want to do that."
The woman said a new roof had just been put on the house.
"I have seen people come and go over the years there. There used to be an elderly lady in there before she passed away."
The Housing New Zealand spokesman said the fire was unrelated to a fire at another Housing New Zealand property in Rotorua yesterday.
Fire crews were called to a home on Emerald St in Pukehangi at 4.30am, after a fire broke out in the kitchen.
A Fire and Emergency northern communications spokesman said an ambulance was called and three people were treated for smoke inhalation.
One was taken to Rotorua Hospital.
The fire spread into the ceiling - and two brigades were called to put out the blaze.
The Housing New Zealand spokesman said "early indications are it was caused by a tenant leaving a pot on a stove".
The tenants have been put up in a motel while a new home was found for them.
