His partner was at Work and Income New Zealand in the hope of receiving financial assistance.
A relative, who runs TK's Fish and Chips in Owhata, said the family had lost everything in the fire.
Detective Sergeant John Wilson of Rotorua said police had yesterday spoken to someone about the incident but had not made an arrest.
"The house is completely gutted. It was definitely arson. It's a relief that no one was killed given there was a house full of mainly sleeping people and it obviously went up quite quickly."
It was not known if all five children lived at the property or whether some were visiting.
The blaze is believed to have started on a couch in the lounge but the cause has yet to be determined.
Part of Pohutukawa Drive was cordoned off for about eight hours yesterday while a scene examination was completed.
Rotorua fire safety officer Stuart Bootten said the house should have had at least five smoke alarms - one for every room - which might have alerted the family sooner.
"It's pretty much all gone. Nothing's really salvageable. All the clothing, all the bedding, it's all heavily smoke-logged and smoke-damaged."