Hunt on for shooter of NSW murderer

A gunman is on the run after a man sentenced to 16 years' jail for murder in the 1990s was shot multiple times in the car park of western Sydney unit block.

Emad Sleiman, 38, was shot in the chest and leg outside the complex on Park Road in Auburn shortly before 9.30pm on Wednesday, police say.

He was taken to Westmead Hospital where his condition improved from serious to stable on Thursday.

Detectives believe the attack was targeted and are looking for a single assailant.

Asked if officers were hunting a lone gunman, Inspector Emma Watson told AAP: "There are various lines of inquiries but we believe that is the case."

Police are yet to determine a motive but believe the dispute could have involved a vehicle.

While it was reported Sleiman had refused to co-operate with police, Insp Watson said the claim wasn't necessarily accurate.

"It's a bit too difficult to determine due to his condition so we haven't been able to speak to him," she said.

"However police will be visiting the hospital at a later stage."

Sleiman was jailed in 1999 for a minimum 16 years after murdering 25-year-old water skiing champion Jason Burton outside the General Bourke Hotel in Parramatta in 1997.

Burton had been celebrating his birthday at the pub when he was confronted and stabbed by Sleiman and one of his relatives concerning an alleged bottom-grabbing incident with a girl.

Insp Watson said public shootings like the Auburn incident posed a risk to community safety.

Detectives are understood to be looking at whether a burnt-out car found in nearby Punchbowl is linked to the attack.