UPDATE 7:45AM: Police forensics and investigators from Fire and Rescue NSW are currently at the scene of a house fire on Matthew Street in Fairy Meadow, Wollongong, in NSW's Illawarra region.
FRNSW Superintendent Scott Dodson said their accelerant detection dogs were also part of the investigation to determine how a single storey fibro house was completely destroyed in the early hours of Wednesday morning.
He said the first call made to Triple 0 were at 2:14am by one of the occupants of the home who stated she was "trapped due to the fire".
She remained on the phone with the FRNSW call-taker as crews were assigned and eventually rescued her from the inferno.
"Four people had self evacuated from that house, and one person was still unaccounted for, so two firefighters have entered through a front door and another two firefighters went through a side window and managed to effect a rescue of a female [who was unconscious]," Supt Dodson told the Mercury.
"The house was very involved when we got here, by fire, so our primary concern was the search and rescue of the lady that was missing."
The woman is was taken by NSW Ambulance helicopter to Concord Hospital's burns unit.
The four others - another woman and three children - were taken to Wollongong Hospital and are currently in a stable condition.
Supt Dodson said at the peak of the blaze 24 firefighters battled to contain it, taking around an hour for it to be extinguished.
No adjoining properties were affected.
UPDATE 7AM: Emergency services remain at the scene of a house fire at Fairy Meadow which has left a 33-year-old woman in a critical condition.
Officers from Wollongong Police District have commenced an investigation into the circumstances surrounding the early-morning fire at the Matthew Street home.
IN OTHER NEWS:
Fire and Rescue NSW evacuated the 33-year-old woman from the home, and she was treated by NSW Ambulance paramedics, before being taken to Wollongong Hospital in a critical condition.
Four other occupants of the home - a woman and three children - managed to evacuate the home before emergency services arrived and were not injured.
UPDATE 5AM: Police have confirmed a 33-year-old woman was critically injured in the blaze. She has since been taken to Wollongong Hospital.
UPDATE 3.15AM: It is understood that of the family who lived in the home, four people were able to escape, and one woman was critically hurt.
EARLIER: NSW Fire and Rescue personnel are "attempting to effect a rescue" at a Fairy Meadow home which caught alight in the early hours on Wednesday morning, a spokesperson said.
A dozen police vehicles, three Fire and Rescue appliances and an ambulance attended the scene on Matthew Street. It has not been confirmed whether anyone remained inside the home.
A NSW Fire and Rescue spokesperson said they were called at 2.14am.
The house was well alight by 2.16am; worried neighbours lined nearby streets, and residents of some adjacent homes evacuated.
One neighbour said they were woken by popping sounds; another said they were woken by the smell of smoke.
One local resident complained loudly of "irresponsible f--- speckles".
The blaze was brought under control by 2.50am.It is not known if anyone was hurt in the incident.