Shots fired at four homes in Sydney's west

Shots have been fired at four homes on the same street in what NSW Police believe was a targeted attack in Sydney's west.

Three neighbouring properties, one other home and a parked vehicle were hit in the attack on Katinka Street in Bonnyrigg about 8.30pm on Tuesday.

All residents were home at the time but no one was injured.

Six shots were fired in total, detectives say, with one bullet passing through a window into a backyard. Fences were also hit.

NSW Police was only informed of the incident almost a day later and believe "one of the homes was the main target of the offenders".

Superintendent Peter Lennon told reporters on Thursday that house is known to police and all residents are cooperating with the investigation.

He is not sure why it took 20 hours before police were called.

"It may be they just heard a noise and didn't think anything of it until daylight the next day," Supt Lennon said.

Anyone in the area or with dashcam footage has been asked to contact police.