A teenager has been charged after an 11-year-old boy was allegedly shot “in the face and neck” inside a luxury apartment in Sydney’s north-west.

The child was fighting for his life in hospital on Monday night and police reportedly said it would be a miracle if he survived.

His “distressed” mother spent the night at the boy’s bedside as he had lifesaving treatment.

Emergency services found the 11-year-old victim with a gunshot wound at a unit in Norwest, Sydney’s Hills District, about 5pm on Monday.

Police outside the upmarket property in Norwest. Photo: Nine Network Photo: 9NEWS

The latest tragedy followed a weekend of violent incidents in NSW.

The boy was shot from inside the home, police said. There was “nothing to suggest” the shooting was related to organised crime.

There were five other people at the apartment complex when authorities arrived — four 18-year-old males and a woman, 44.

Superintendent Naomi Moore on Monday said the group — some relatives, some friends — were “allowed access” into the home.

Three of the men, all aged 18, were arrested.

Two were taken to The Hills Police Station and later released pending further inquiries.

The third man was taken to Riverstone Police Station, where he was charged with conceal serious indictable offence. He was refused bail and will appear before Blacktown Local Court on Tuesday.

Moore said police had no reason to suspect the shooting related to organised crime, but she would not speculate what occurred in the house.

She said the boy’s mother accompanied him in hospital.

“She is as distressed, as any parent would be, about what she is dealing with at the moment,” Moore said.

“It is an [absolutely] tragic situation and, as we’ve seen some tragedy across Sydney in the last couple of days, this is not far from the worst that I have seen.”

Moore said police were yet to find a firearm, but no firearms were registered to the Fairway Drive address.

That fact would form a line of inquiry, she said.

Police established a crime scene at the address and the investigation continues.

Anyone with information has been urged to contact Crime Stoppers.

-with AAP