By Alex Mitchell and Peter Bodkin in Sydney

A domestic dispute allegedly escalated into a father burning down his home and stopping rescuers saving his children in what police have described as one of the worst-known cases of filicide.

Investigators are unpicking the events that led to the house fire in western Sydney that left three young children dead and a man facing multiple murder charges.

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 home at Lalor Park.

Three of his children, aged six, two and five months, died in the fire early on Sunday morning, while three others were hospitalised.

The man has been charged with three counts of domestic violence-related murder and five counts of attempted murder.

Police allege the man 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.

“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 heard 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 contacting family members, attempting to find them or going within 500m of where they lived.

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 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.

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 their mother 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, who he could hear coughing and yelling from inside the house.

An online fundraiser started by Mr Hawkins for the surviving family members had raised nearly $30,000 by Thursday afternoon.