Firefighters discovered the 37-year-old woman and her daughters, aged eight and ten, unconscious in an upstairs bedroom after a gas bottle explosion.

Fire Rescue Victoria confirmed that the explosion was likely caused by a gas cylinder inside the house, although the exact cause of the fire is still under investigation.

Detectives are awaiting the mother's recovery to interview her about the incident, but they currently have no other suspects.

Authorities have deemed the blaze suspicious and established a crime scene, with an arson chemist on-site to assist in the investigation.

The fire was brought under control by approximately 10:15 PM, but it caused extensive damage, including a partial structural collapse of the townhouse.

At the height of the blaze, 30 firefighters and 11 trucks were deployed to manage the situation and monitor for hotspots throughout the night.

Police are questioning a 36-year-old man, the fourth occupant of the home, who has been ruled out as a suspect as he was not home during the incident due to his night shift job.

Emergency services responded to the blaze on Terrigal Street around 9:40 PM, with firefighters arriving shortly after to find flames engulfing the rear of the two-storey townhouse.

The mother was transported to The Alfred Hospital, while her daughters were taken to the Royal Children's Hospital, where all three remain in critical condition.

A mother and her two daughters are in critical condition following a suspicious fire at their townhouse in Chadstone, Melbourne, on May 21, 2025.

Witnesses reported seeing a large fireball and smoke filling the street shortly after the fire started, with one neighbor noting an explosion just before the flames erupted.

Authorities encourage anyone with relevant information or footage to contact Crime Stoppers at 1800 333 000.