The police were called to assist Fire and Emergency New Zealand at the house fire around 4.20pm, a spokeswoman said yesterday evening.
A scene guard was put in place overnight on Saturday and the police returned to the fire site yesterday morning to carry out a scene examination.
"Police and fire investigators are making inquiries to establish the cause of the fire," the spokeswoman said.
The police said earlier on Sunday that the fire was being treated as suspicious.
Blake Davison, who was also across the street from the burning house, said he heard a commotion and went to see what was going on.
"The fire engines were pulling up at the same time that I arrived, so they got out here pretty quickly."
He said the fire was already well underway by that time and a fair crowd had already gathered.
"There was a lot of heat, a lot of popping and cracking coming from inside the house. The Fire Service had it all under control pretty quickly though. We were just praying that everyone was okay."
When the Bay of Plenty Times visited the burnt-out property on Sunday, Fire and Emergency New Zealand investigator Stuart Bootten said it was being treated as a crime scene and an investigation was underway.
He said no one was home at the time of the fire and a passerby had alerted Fire and Emergency New Zealand.
"The safety message is rural properties really need to look after themselves because of the distance from fire stations and that is considering . . . sprinkler systems for a home. They will control the fire to a very small area until we get there," Bootten said.
"And of course having working smoke alarms giving the early warning."