"We're appealing for any witnesses in the Kuripuni area around that time."
The fire was started in the far flat of a three-unit property, though Mr Smith said it was contained to the one unit and the other residents were not in any danger.
The unit is owned by Allen Wilton, who is in Sydney until September, and his brother Denman Wilton called him yesterday morning to tell him about the incident.
"He said 'there's not much I can do about it from here is there?'," said Denman of his brother's reaction.
Mr Wilton heard about the fire from another tenant in the unit, and said he would be supporting his brother to work through insurance claims and liaise with police.
He said he did not know the tenant of the unit, but thought the fire might have been gang-related.
"Comments have been made lately that there's been patched [gang] members strutting around next to the property on High St lately."
Detective Smith said it was very early in the investigation and they were keeping their minds open to any lines of inquiry.
Electricity to the property was turned off during the investigation but was restored later in the day.
An elderly couple in the adjoining unit declined to comment on the fire.