Multiple arrests have been made after investigations into synthetic cannabis suppliers.
Operation Hypnos targeted multiple addresses across Auckland police believed were being used for the manufacture and supply of synthetic cannabis.
Police found a "significant" amount of synthetic cannabis when they raided properties across the city yesterday.
Six arrests have also been made in Christchurch after several search warrants were executed earlier this morning.
About 3kg of the drug was seized from five Auckland addresses.
Three people were charged with possession for supply of synthetic cannabis and have appeared in the Manukau District Court.
Another person was charged in relation to possession of cannabis.
More charges may be laid, said Inspector Mark Benefield, relieving Manurewa area commander.
Methamphetamine, cannabis, six firearms and cash were also seized during the raids.
Across Christchurch, Canterbury police executed five search warrants this morning, resulting in six arrests.
Two women and three men were charged with possession of synthetic cannabis for supply or sale.
A sixth person was arrested in relation to an historic family harm matter.
Three are appearing in the Christchurch District Court this afternoon, and the rest will appear over the next few days, said Detective Inspector Greg Murton.
During the searches around 114 bags of synthetic cannabis prepared for sale were seized.
Each bag weighed 1g and had a street value of $20, totalling $2300.
A firearm and around $2000 in cash were also found along with evidence psychoactive substances had been imported.
Police were working closely with health boards, Ministry of Health, Coronial Services and St John to warn the public about the dangers of the drug, which has killed 10 people in the past month, Benefield said.
"We have seen first-hand the damage synthetic cannabis can do and the danger it poses to the community. We urge those who are using synthetic cannabis to stop immediately and seek help if you need it.
"We are doing everything we can to get this drug off our streets and keep our communities safe."
Anyone caught making or supplying synthetic cannabis would be arrested and charged, he said.
Anyone who knew who may be making or supplying synthetic cannabis was asked to contact their local police station.
Information could also be provided anonymously to Crimestoppers on 0800 555 111.