Explosion severely burns woman in Ruakaka

File photo / Supplied

A woman who has suffered burns to 70 per cent of her body had just arrived home when an explosion occurred, a resident who came to her help says.

Investigators will return to a Northland home this morning to determine what caused a fire that has left the woman in hospital.

There were reports of an explosion at the home on Tamure Place in Ruakaka, south of Whangarei, about 8.30pm yesterday.

The woman was rushed to Northland Base Hospital in a serious conditions with severe burns.

Nearby resident Jill Russell, 79, said she heard "a huge bang from about a mile away".

She ran outside and saw flames shooting through the roof.

Mrs Russell saw the woman outside the house with burns to her face and her clothes torn.

She went to help the injured woman, who she said had just arrived home from work and opened the door when the explosion occurred.

"It was terrible," Mrs Russell said.

"But when you are 79 years old you've seen a lot and you can handle these things.

"There are quite a few upset people tonight, I'm sure."

She said ambulances and fire trucks arrived within five or six minutes.

The home was well involved when firefighters arrived at the scene.

"We had multiple calls from neighbours who said it sounded like an explosion, which also rocked a number of nearby houses," Fire Service northern communications shift manager Dallas Ramsay said.

"We had four trucks there ... battling the blaze."

The scene has been under guard overnight and fire investigators will return to the home this morning.