A man has suffered minor injuries after he was shot at while answering the front door of his house in Sydney's west.

Police have established a crime scene at the home in Merrylands.

A single bullet grazed the man's neck.

Two small children and their mother were also inside at the time the shot was fired, but they escaped without injury.

In January this year, New South Wales Police launched Operation Spartan in an attempt to rid western Sydney of a spate of gun crime.

Last month, detectives discovered an Australia Post branch was being used by a syndicate which brought up to 220 illegal guns into the country, some of which were linked to the recent Sydney shootings.

Detectives have been scrambling to track down scores of guns they believe were sold by the ring.