Detective Senior Sergeant Nik Leigh said the investigation was still in its early stages and it was unclear what had started the fire which happened on Friday night.
A number of lines of inquiry were being investigated, and one of those was to do with the condition of the house.
"At this stage there’s no suspicious circumstances," he said.
A number of people had been spoken to and police had a pretty clear idea of what happened, but still wanted to speak to anyone who had any information about the fire.
The fact that the building was a boarding house, with separate rooms, would would be a focus of the investigation.
The Ministry of Business, Innovation and Employment (MBIE) would be involved in the investigation to consider compliance, as the location was a commercial residential business, Det Snr Sgt Leigh said.
MBIE tenancy compliance and investigation team acting national manager Andrew Galloway said the Tenancy Compliance and Investigations Team was in the early stages of an investigation at the property.
The team’s job was to monitor and enforce compliance with the Residential Tenancies Act 1986 and had powers to undertake retroactive investigations of boarding house tenancies, Mr Galloway said.
Broad changes to tenancy law, introduced with the Residential Tenancies Amendment Act 2020, were now in force.
Boarding house landlords who intentionally failed to meet their obligations could be liable for penalties of up $50,000.
Healthy homes standards meant private boarding houses must now be fully compliant with standards across five categories: heating, ventilation, insulation, moisture and draughts, Mr Galloway said.
Landlord Kerrie Matthews said she had not yet talked to any investigators.
She would co-operate with anyone, she said.
She was confident that the boarding house was compliant with the Residential Tenancies Act, she said.
Fire investigator Nick Linton did not respond to requests for comment.
