Bonnyrigg nail gun attack: Stepson charged over 'nail gun attack' on Christmas Day

A young Sydney man has been charged with intent to murder after he allegedly attacked his stepmother with a nailgun on Christmas Day.

Police allege Akaash Narayan, 20, grabbed a nail gun from his car before firing the weapon from close range at his stepmother's head at 10.30pm on Tuesday.

He was charged overnight with wounding with intent to murder.

He was refused bail and will appear at Parramatta Bail Court today.

Ragni Narayan, 50, was shot in the head multiple times in the driveway of her home in Bonnyrigg Heights in Sydney's west at 10.30pm yesterday.

Mr Narayan allegedly fled the scene on foot before being arrested at 3.45am.

Mrs Narayan is in a critical condition.  

Neurosurgeons were due to carry out tests today to determine whether she's been left with permanent brain damage.

Police are still unsure what caused the alleged fight that has ripped the Sydney family apart.

Her distraught husband was comforted by a friend as he was interviewed by police.

Neighbour Slavija Sbasa said: "It was a bang, a really loud bang. And then I heard screaming."

Fairfield Police Station acting Inspector Paul Luczak said the incident was "horrific" and that the woman had "severe injuries to her head".

"I believe it was three times she was hit in the head," he said. 

"They were celebrating Christmas and we're not sure what actually started the incident. It was just immediate family there.  

"I believe the husband of the victim was in shock and treated by paramedics. 

"The alleged attacker fled the scene on foot but was later arrested in a street not far from the incident.

"Christmas is traditionally a hard time for police because there is an increase in domestic violence incidents."

Anyone with information about this incident is urged to call Crime Stoppers on 1800 333 000.