Mourners attended a vigil, some carrying flowers with them, at Lalor Park in western Sydney on Thursday evening.
"It is important to come together, not to find answers, but for support," community support group Carevan Blacktown said in a flyer for the event.
Police have joined members of the community at a vigil for the victims of a shocking house fire. (Thomas Parrish/AAP PHOTOS)
It comes after the children's father was charged with three counts of domestic violence-related murder and five counts of attempted murder over the fire.
The 28-year-old did not appear during his first court date on Thursday when he was expected to face a bedside hearing after being left in a coma following the blaze at his Lalor Park home.
Three of his children, aged six years, two years and five months, died in the fire early on Sunday morning. Three other children were taken to hospital.
Police have described it as one of the worst-known cases of filicide.
The man allegedly locked the doors to his house before using petrol to accelerate a mammoth blaze, preventing officers and neighbours freeing the victims.
Homicide Squad commander Daniel Doherty said rescuers had to wrestle children from the man's grasp once they forced their way into the property.
A horror house fire that claimed the lives of three children has shocked Lalor Park residents. (Thomas Parrish/AAP PHOTOS)
"These are tragic circumstances, one of the worst cases of filicide that we've had in NSW in recent memory," he said.
"We will allege this person is solely responsible (and) will be held accountable for his actions."
The man was left in an induced coma because of severe burns and smoke inhalation, but he woke on Wednesday night.
He did not appear when his matter was heard in Parramatta Local Court and his lawyer made no application for bail.
Magistrate Joy Bolous was told the man had no criminal record and had only appeared before the court on tax-related matters.
She put in place an apprehended violence order to prevent him from contacting family members, attempting to find them, or going within 500m of where they lived.
UPDATE: Murder charges laid over fatal house fire - Lalor Park— NSW Police Force (@nswpolice) More details - https://t.co/cgDgBPGvshJuly 10, 2024
The man is also accused of destroying or damaging property with the intent of endangering life.
A welfare check triggered by a concerned neighbour led to a police call-out to the property weeks before the fire, but no issues were identified at the time.
"(They're) the most violent acts you could imagine … we allege there was some type of domestic argument or dispute that may have led to this incident happening," Detective Superintendent Doherty said.
"It's quite unusual circumstances.
"One would expect there would have been several interactions or certain other events that might have taken place."
The slain children's 29-year-old mother had recovered physically after the fire and completed a walk-through of the crime scene with police.
The attempted murder charges relate to four other children - aged between four and 11 - and the woman.
The man who allegedly tried to stop people entering the burning home faces murder and other charges. (Thomas Parrish/AAP PHOTOS)
Several of the children remain in hospital but they are expected to be released as soon as Thursday afternoon.
The man is expected to make a full recovery and is next due to appear in Penrith Local Court on September 6.
Investigators put the survival of the four remaining children and the woman down to the heroic efforts of neighbours and emergency responders, some of whom suffered minor injuries.
Neighbour Jarrod Hawkins said he smashed down the front door and rescued several children after he could hear coughing and yelling from inside the house.
An online fundraiser started by Mr Hawkins for the survivors had raised almost $30,000 by Thursday afternoon.
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