The Fire Service said it was called to the fire in Collingwood Street in Hamilton just after 5am. Photo: RNZ / Andrew McRae
Police today officially named the three as Toni Maree Johnston, 23, Jake Lindsey Hayes, 19, and Connor James Swetman, 17.
At a police news conference this afternoon, Ms Johnston's brother, Greg Johnston, spoke on behalf of their family.
"One phone call on Saturday morning completely changed our lives. It has been the worst week of disbelief, hope, heartbreak, anger and incredible sadness," he said.
"This process has been exhausting, and we still have many unanswered questions."
Mr Johnston said the family would be forever grateful to both the Police and the Fire Service.
Detective Senior Sergeant Ross Patterson said investigations at the house had been completed and the property handed back to its owners.
"Post mortems were carried out in Auckland earlier this week and now the trio have been returned to their families," he said.
"From a police perspective, the cause of the fire is yet to be determined. We are awaiting forensic results."
The fire was being treated as suspicious until proven otherwise, Mr Patterson said.
Meanwhile, a person died in a fire in the Christchurch suburb of Linwood this afternoon.
A Fire Service spokesperson said crews were called to the Woodhouse Street house about 2.15pm.
It was well ablaze and extensively damaged when crews arrived, and a person was found dead at the scene.