Two fighting for life after suspicious house blaze

Two women are fighting for life following a house fire authorities consider suspicious.

Detectives are investigating the cause of the Boxing Day blaze, which erupted shortly after 3am in Gulliver, a suburb of Townsville.

The pair, aged 53 and 83, were rushed to Townsville University Hospital with critical airway burns, while a third resident, a 55-year-old man, was taken to the same facility with non-life threatening injuries.

With a crime scene declared, investigators are appealing to witnesses or anyone with CCTV or dashcam vision to come forward.

Neighbouring houses were evacuated in response to the heat generated by the fire.

A Queensland Fire Department spokesman told local media the house was engulfed by flames, with crews still working to extinguish them four hours later.

"We had a house that was well involved when we arrived," he told the Cairns Post.

"We had four crews on scene."

A woman was also airlifted to hospital on the state's Sunshine Coast on Christmas Day after she toppled into a backyard fire pit.

A LifeFlight spokesman said the patient, in her 70s, suffered severe burns to her back and abdomen.

One of the service's emergency choppers landed at a nearby school oval about 3.30pm as ambulance paramedics treated the woman at the scene.

She was then flown Royal Brisbane and Women's Hospital.

Meanwhile, a fire of a different kind also had authorities scrambling after the smell of burning eggs led to an alarm being triggered in central Adelaide on Christmas morning.

Police and fire crews arrived to find the premises thick with smoke but soon discovered test tubes, beakers and a suspicious fermenting substance that raised the spectre of a clandestine drug lab.

The immediate area was cordoned off to protect the public, while a 35-year-old male resident was arrested and later charged with manufacturing a controlled drug and possession of prescribed equipment.

He has been granted police bail to appear in Adelaide Magistrates Court at a later date.