He said the syndicate had been selling the guns in “plain sight” at parks and shopping centres.
Detective Superintendent Watson said the seizure of the weapons meant NSW was safer.
“We all know it only takes one bullet,” he said.
Mr Shen was allegedly directing the group while his wife was “well entrenched” in the activities.
The pair were arrested at their Cherrybrook home at 6am on Thursday and taken to Ryde police station.
Police charged Mr Chen with 18 firearm and drug offences including unlawfully selling firearms, manufacturing a prohibited drug in a greater-than-commercial quantity, and knowingly directing a criminal group.
Ms Ngoc was charged with 45 firearm offences including unlawfully selling firearms, participating in a criminal group, and contributing to criminal activity.
They were both refused bail and will appear in Hornsby Local Court on Friday.
A day spa in Double Bay where Mr Langi works was also searched and police allegedly found two cases used to store and transport guns.