Detectives arrested a 35-year-old man at a correctional facility at Wellington about 10.45am on Monday.

He was charged with three counts of supplying a prohibited firearm to an unauthorised person and three counts of supply firearm to a person who was unauthorised to possess it.

Police will allege in court that the man negotiated the sale of firearms to the criminal syndicate which included a Glock, a revolver and two shot guns, between October and December 2019.

In the news:

Earlier this year, detectives from the Robbery and Serious Crime Squad uncovered a sophisticated criminal network involved in large-scale drug and firearm supply, which was operating out of Sydney's south-west, as part of investigations into unsolved serious and organised crimes across NSW.

In May, investigators arrested a 38-year-old man, the alleged director of this criminal group, who was also charged with multiple drug and firearms-related offences. He remains before the court.

The man who was arrested at Wellington on Monday will face Wellington Local Court on Tuesday.

Anyone with information in relation to criminal activity in their community is urged to contact Crime Stoppers on 1800 333 000 or nsw.crimestoppers.com.au.

Information is treated in strict confidence. The public is reminded not to report crime via NSW Police social media pages.