More than 140,000 cannabis plants were seized and more than 1100 people arrested in police's national cannabis operation.
The number of plants destroyed during the 2008-09 operation increased by 17,000 from 2007-08, Detective Senior Sergeant Scott McGill at Police National Headquarters said.
More than 820 searches had been conducted inthis year's operation, leading to about 141,000 plants being destroyed , 1125 people arrested, 191 firearms seized and about $400,000 worth of stolen property recovered.
Based on the New Zealand Drug Harm Index, it was estimated that $379 million worth of social harm had been prevented by the operation, Mr McGill said.
"The results show the commitment and dedication that police staff around the country have to reducing the harmful effects of illicit drugs in our community."
Mr McGill said members of the public had also made major contributions to the success of the operation by providing invaluable information that lead to plots being located and offenders arrested.
