A cache of machine guns, pistols and ammunition have allegedly been uncovered by police during the arrest a former officer.
Ballistic vests, a 3D printer and firearm parts including barrels and triggers were also found, police allege during the 45-year-old's arrest on Monday in the Illawarra region of NSW.
He was charged with recklessly directing a criminal group and 19 other charges relating to the supply, manufacture and possession of firearms and ammunition.
"This was a highly sophisticated firearm manufacturing process that they (criminal elements) had established, which included a 3D printer," Raptor Squad commander Detective Superintendent Andrew Koutsoufis told reporters.
"We haven't seen firearms of this quality too often so we're very happy to have seized these firearms and to have taken these people off the street."
He added the syndicate was "actively attempting" to sell their 3D-printed arsenal to other gangs involved in serious and violent crimes.
A 16-year-old boy was also arrested and charged with 16 offences including participating in a criminal group.
Both were refused bail on Tuesday.
Another 43-year-old Queensland man was arrested and will be extradited to NSW.
Police said on Tuesday more arrests are expected in the course of the investigation, which has been ongoing since January.
Det Supt Koutsoufis said the former cop has not been with the force since 2012, adding his alleged actions are completely antithetical to the values of NSW police.
"The alleged actions of this 45-year-old ex-law enforcement officer, in my view, are completely abhorrent to the values that I stand for as a law enforcement officer," he said.
Four men were arrested in March for alleged roles in a gun ring supplying homemade weapons across the NSW-ACT border.
Alongside the guns, police say they also seized memory cards containing blueprints to manufacture more weapons with 3D printers.
NSW and Tasmania are the only jurisdictions so far to legislate against possessing digital blueprints for firearms.
