Emergency services were called to an intersection of the Great Western Highway in south Wentworthville about 12.45pm on Thursday, but paramedics were unable to save the 35-year-old man.

Police have set up a crime scene and begun investigating, with initial inquiries indicating a vehicle found torched on a nearby street is related to the incident.

A crime scene has been established there too, with both to be examined by specialist forensic officers.

Police are now searching for the culprits, telling reporters at least two people - a driver and a shooter - are believed to have been involved.

The incident is understood to be the latest escalation in a long-running feud between the Hamzy and Alameddine families.

While Acting Superintendent Glen Fitzgerald declined to confirm the victim's identity, citing the early stage of the investigation, he said police believe the incident is linked to criminal groups.

"Again, (we have) a very brutal attack that's happened during the daylight hours in Sydney," he said.

"The shooting is quite obviously targeted."

Officers will be canvassing the area and knocking on doors to gather information, and anyone with information is urged to contact CrimeStoppers, he said.

Bassam Hamzy's brother Mejid Hamzy was in 2020 ambushed early in the morning in front of his Condell Park home and his cousin, Bilal Hamze, was executed by gunmen in Sydney's CBD in June last year.

Two other members of the extended Hamzy family - father and son Toufik and Salim Hamze - were also shot dead in Guildford in October.

NSW Labor police spokesperson Walt Secord says the string of incidents shows the state government needs to do more to stamp out gang crime.

There have been almost 30 major violent incidents between gangs in NSW in the past 18 months, he said.

"Crime gangs are carrying out attacks with impunity."

"Frankly, I'm less concerned about feuding gangsters killing each other - and far more concerned about innocent bystanders getting killed in the cross-fire."

Australian Associated Press