NSW police have seized and destroyed 12,000 cannabis plants with an estimated street value of over $22 million in the past year.

The Cannabis Eradication Program, a drug protection program run by NSW Police, targeted cannabis crops in New England, Richmond, Coffs Clarence and Tweed Byron Local Area Commands.

Police destroyed 12,000 plants, with over 4,800 plants found in New England alone, a substantial increase on recent years.

Drug squad commander, Detective Superintendent Tony Cooke, said the program was an invaluable tool.

"Preventing large amounts of cannabis will have an impact on the availability of cannabis in these areas, disrupt the supply chain, and minimise the harm caused by the drug," he said.

Many of the crops were located in dense bushland with crops ranging from a few plants to several hundred.

"That's a substantial increase over a number of years and for us goes to demonstrate the continued importance of the program in removing significant numbers of cannabis plants from the community, interrupting supply and making sure that cannabis does not make it to our streets," Detective Cooke said.

Police said to date 13 people would face court on drug-related charges while inquiries continued.

Detective Senior Sergeant Andrew Graham said police would continue to target similar areas in the coming years.

"We found plantations with several hundred plants at a time," he said.

"Often they're secreted in smaller batches to avoid detection."

The CEP has seized and destroyed around $300 million worth of plants since the 1980s when the program was introduced.