Police have made significant arrests in relation to the supply of synthetic drugs.
Waitemata police seized product which would have had a street value of around $1.5 million when manufactured.
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This comes as part of Operation Tiger, an ongoing effort to target those importing psychoactive substances.
The investigation began after Customs seized a kilogram each of AMB-Fubinaca and AB-Pinaca, the psychoactive substances often used to make synthetic drugs.
Last month, nine related search warrants were executed in Auckland, Palmerston North and Christchurch.
The most significant find was a storage unit in Rodney, where 11kg of finished synthetic drugs were found and another kilogram of AMB-Fubinaca.
A 58-year-old man was arrested on Thursday and charged with importing, manufacturing, and possession for supply of a psychoactive substance.
He will appear in North Shore District Court on Wednesday.
Operation Tiger is ongoing and police have not ruled out the possibility of further arrests.
In a separate, unrelated investigation into two recent deaths suspected to be linked to synthetic drugs, police have arrested three people for supplying the synthetic drugs the deceased are believed to have used.
The three men arrested are aged, 22, 30 and 33, they have all been charged with selling/supplying a psychoactive substance.
Waitemata police Detective Inspector John Sutton urges the community to report those selling the drugs.
"We need your help to catch these offenders so please do not hesitate to contact us with any information, we can assure you, it will be taken seriously."
If you have any information that can assist police in catching the offenders, please contact your local Police Station or call Crimestoppers anonymously on 0800 555 111. If you have any concerns about the health of someone who has consumed synthetic drugs, call 111 and ask for an ambulance.