The men, aged between 20 and 25, were gunned down outside a Smithfield residence just after 8pm on Friday.
About 15 bullet holes were found in a garage door at the property.
The men were taken to hospital for non-life threatening injuries, including gunshot wounds to the stomach and leg.
A number of Nomad bikies were seen in the area after the incident, according to Fairfax Radio Network.
Police say the men were known to them but didn't appear to have any links to bikie gangs.
"There's nothing to indicate that it's bikie-related," a police spokeswoman said on Saturday morning.
Police said they believed the incident was a targeted attack.
Acting Assistant Police Commissioner Arthur Katsogiannis said the shooting ‘‘relates to a conflict between groups which are known to police’’.
He said police were worried about reprisal action in the wake of the shooting.
‘‘Certainly, we’re concerned about retaliations,’’ Mr Katsogiannis told reporters on Saturday.
‘‘We’ll be working very, very closely with the local area command investigators to ensure that we target those areas and individuals.
‘‘We know who the individuals are in these groups.’’
Police were investigating the possibility that the incident could be linked to another shooting in the area on April 22, Mr Katsogiannis said.
He said a silver Holden Commodore was seen
fleeing the scene shortly after the shots were fired on
Friday night.
Police would be reviewing CCTV footage of the bullet-sprayed
house.
Police hadn’t yet spoken to any of the injured men, Mr Katsogiannis said.
