Young girl flees fierce flames to alert firefighters others trapped in Flat Bush home blaze that killed three

An 11-year-old girl bravely escaped a deadly blaze to tell firefighters people were trapped inside her burning home.

A police cordon has been set up around the Plantation Ave property in Flat Bush as an investigation starts into the cause of a house fire that has claimed three lives.

It is now feared children were among the casualties in this morning's devastating pre-dawn blaze.

Six people were inside the house when the fire broke out. Three people were taken to Middlemore Hospital, including an 11-year-old girl and 47-year-old man.

Fire Service area commander Larry Cocker said a youngster managed to get through the blaze to reach firefighters and tell them others were still behind the wall of flames upstairs in their bedrooms.

With windows exploding and smoke billowing from the two-storey home fire crews immediately started attacking the fire to enable a rescue crew to venture into the burning property and pluck those still alive to safety.

It wasn't long before firefighters soon found the destructive blaze had claimed a grim toll.

"We fairly quickly established people were deceased in the property," said Cocker.

"We saved the saveable but then focused on getting the fire out."

Cocker said today's triple fatality was the worst possible outcome.

"For those of us who are in the business it's not a great day at the office.

"These are the outcomes we spend our working lives trying to avoid.

"When it happens it's a tragedy and leaves us scratching our heads."

Neighbours have told of hearing desperate screams and exploding glass shattering the stillness of the sleeping street.

Plantation Ave neighbour Christa Stone said at least three children lived at the house.

"They'd just bike up and down with each other. It's just kind of sad because there's going to be one or two less."

Resident Julie Pedrido said she heard commotion but did not realise how serious it was.

"All I heard was screaming - I just thought people were arguing - and then glass breaking. I just thought people were throwing things at each other."

Police at the scene of a house fire that killed three people in South Auckland. Photo / Michael Allen

She said the deaths were a tragedy for the street, especially so close to Christmas.

"I'm really shocked because I live right across the road, and I feel really bad because I didn't even know," she said.

"I just woke up to fire sirens and the police.

"And then I looked out the window and I couldn't really see the fire, I just saw light and smoke," Pedrido said.

Another resident posted on Facebook: "We are right next door. Can't get the father's cries out of my head. So horrible."

A Plantation Ave resident, who asked not to be named, said she woke up about 3:20am.

"There was glass breaking and people screaming. It wasn't nice."

She then heard sirens blaring as fire engines rushed to the scene.

Fire Service Northern shift manager Scott Osmond said six people were in the Flat Bush home when the fire broke out at 3.25am.

Osmond said the two-storey Plantation Ave property was engulfed by fire when crews arrived within minutes of the alarm being raised.

He said firefighters at the scene were told people were inside the home and mounted a search and rescue operation.

"There were multiple calls to the fire. We got there within five minutes and the house was well involved in fire," he said.

"We had information that people were in the house and unfortunately it turned out there was."

A police cordon remains in place outside the house in the quiet subdivision. A fire engine, two other fire appliances and two police cars are still at the house.

Police at the scene have said it has been a sad task to deal with just days out from Christmas.

The top storey of the house is gutted with all the windows blown out.

Neighbours say the property had only been sold a few months ago.

The home is a recently built property in a new subdivision and was sold earlier this year.

It was not clear if those inside the home were related.

A hospital spokesperson said one person was in a critical condition and two others were stable.

Victim Support is with the survivors.

Chief executive Kevin Tso said it was tragedy, particularly striking just before Christmas.

Detective Inspector Gary Lendrum said the fatal fire was being treated as "unexplained".

Police and specialist fire investigators were now beginning a detailed scene examination inside the gutted Plantation Ave home.

It was hoped they would be able to be in a better position on understanding how the fire started later today, he said.