A man and a woman have been killed and a teenage girl is in a critical condition after a family home was destroyed by fire in Brisbane's north.

Authorities say the bodies of the man and woman were found in their bed.

A neighbour says the 17-year-old girl ran screaming from her Bracken Ridge home, covered in horrific burns to her face and body.

She is in a critical condition in the Royal Brisbane Hospital with burns to her chest and face, firefighters say.

A man, 20, his 21-year-old girlfriend and a dog escaped out a second storey window after the house on Peter Close was engulfed in fire early on Friday.

Firefighters were called to the scene around 4am (AEST) after neighbours raised the alarm.

A man in his 40s, believed to be the teen girl's father, and a woman believed to be her stepmother, did not make it out of the house.

The 20-year-old man has minor burns to his legs and injuries to his feet and hand from jumping from the house, Queensland Fire and Rescue Service senior operations supervisor Brad Hardy told reporters.

The older woman is in a serious but stable condition with burns to her arms and legs and cuts to her feet.

Neighbour Rangi Piekau said she heard loud bangs and screaming and found her 17-year-old neighbour on the street with horrific burns.

"We took her into our place and kept her in there until the ambulance came," she told AAP.

"I was freaking out because there was nothing else I could do to help."

She said she knew the children by name and the father had taught her daughter how to mow the lawn.

"They were lovely people, a lovely family," she said.

Firefighters brought the blaze under control at about 5.20am (AEST).