CHARGES have been laid following investigations into an alleged large-scale drug supply syndicate operating in the state's north, including the alleged arranging supply of a drug into the Grafton Correctional Centre.

Strike Force Trevalsa was formed in January 2018 by Richmond Police District Drug Unit, to investigate the ongoing supply of large commercial quantities of illicit drugs on the state's north coast.

Since the strike force commenced four men have been charged and are now before the courts.

Strike Force officers, in conjunction with the Corrective Services NSW investigations unit recently identified a 23-year-old inmate allegedly arranging the supply of Buprenorphine into a correctional centre, including police allege the Grafton Correctional Centre.

Strike force officers yesterday arrested the man at a correctional centre and charged him with 11 counts of supply prohibited drug and one count of participate criminal group contribute criminal activity.

He is due to appear at Lismore Local Court on Monday July 16.

Richmond Police District Crime Manager, Detective Chief Inspector Cameron Lindsay commended the joint investigation with Corrective Services NSW investigators.

"Our priority is to protect the community and remove these deadly drugs from our streets, but also to ensure those incarcerated and before the courts do not continue to commit offences.

"We encourage the community to report anything suspicious to Crime Stoppers on 1800 333 000. Information can be given in confidence" said Detective Chief Inspector Lindsay.

Strike Force investigations will continue and further charges are expected.