"The owners of the house were staying with their friends at the time.
"The fire started in the lounge and resulted in the roof collapsing."
Cooper said there was significant damage done to the property and "unfortunately it was not safe enough to go back inside to check whether they had a working fire alarm".
"The property is unliveable," Cooper said.
Three fire trucks, from Hastings and Napier stations, as well as support units fought the blaze until it was put out about 4am.
The fire is being investigated by police and the cause is yet to be determined.
