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 Ghassan Amoun.
Police have set up a crime scene and suspect 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 Hamzy and Alameddine crime families have been engaged in a long-running feud.
Although police have not put forward any suspects, Acting Superintendent Glen Fitzgerald said 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 clues, 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 spokesman 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," Mr Secord said.
"Frankly, I'm less concerned about feuding gangsters killing each other – and far more concerned about innocent bystanders getting killed in the cross-fire."
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