In November 2019, detectives from the State Crime Command's Drug and Firearms Squad established Strike Force Harthouse to investigate the cultivation of cannabis across NSW.

Their inquiries uncovered a property just north of Glenreagh using 13 large industrial grow houses to cultivate cannabis.

Following extensive inquiries, strike force investigators, with assistance from Coffs/Clarence Police District, the Rural Crime Prevention Team, Coffs Harbour Region Enforcement Squad, and the Dog Unit, arrested five men - aged 25, 41, 45, 48 and 53 - and a 46-year-old woman at a rural property at Kremnos, about 30km south of Grafton, about 7am yesterday (Wednesday January 22).

A crime scene warrant was executed at the property where investigators seized about 5,200 cannabis plants, with an estimated potential street value of $15.6 million, and about 200kg of cannabis head, with an estimated potential street value of $1.4 million.

After dismantling the large set-up, investigators also seized hydroponic, electrical, and lighting equipment, as well as chemicals.

The men and woman were all taken to Coffs Harbour Police Station and charged with cultivating a prohibited plant (large commercial quantity), supplying a prohibited drug (large commercial quantity), and participating in a criminal group / contributing to criminal activity.

They were all refused bail to appear at Coffs Harbour Local Court today (Thursday January 23).

Investigators are working with the Department of Home Affairs regarding the immigrant status of the group.

Drug and Firearms Squad Commander, Detective Superintendent John Watson, said this is the second rural property found cultivating commercial quantities of cannabis in the area in two months.

"We found a sophisticated illegal cannabis plantation which had been set-up for the sole purpose of cultivating cannabis to make a profit," Det Supt Watson said.

"The grow houses were 60x20 metres in size and to neighbouring properties they may have appeared to be fruit crops.

"These arrests should send a strong message to criminals using regional NSW to grow cannabis crops that you will not go unnoticed.

"The seizure of 200kg of cannabis head that had been harvested and prepared for the streets will cut into the profits of this criminal network and disrupt any intention they may have had to re-invest the profits into other illicit enterprises across the state."