Three people have been arrested over supplying synthetic drugs in Auckland, with the substance being linked to 10 deaths this month.
Inspector Mark Benefield said search warrants had been carried out across Auckland as part of 'Operation Hypnos', which targeted addresses suspected of manufacturing and supplying the substance.
Mr Benefield said police were acting on information received from the public around suspected suppliers of the drug.
He said three kilograms of the synthetic drug was found at five properties, with three people charged in relation to possession for supply.
They have appeared in the Manukau District Court.
Another person has been charged in relation to possession of cannabis and police said further charges could be laid.
Police also seized methamphetamine, cannabis, firearms and cash during the raids
Inspector Benefield said police were working with District Health Boards, the Ministry of Health, Coronial Services and St John to ensure people are well aware of the dangers of the drug.
"We urge those who are currently 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.
A criminal law expert said manufacturers and suppliers of synthetic drugs could be charged with murder or manslaughter if deaths linked to the use of the substances are traced back to them.
Steve Bonnar said manufacturers could be found guilty of murder if they knowingly add poisonous substances to a drug and a person taking it dies.
He said that's the same for suppliers who then sell the drug, knowing it would cause harm to others.
"There are a number of that you can get to either murder or manslaughter. If someone dies because of an unlawful act, and I would have thought selling a unapproved synthetic cannabinoid and putting poison in it for example, that's clearly an unlawful act."
Last week, St John said that it was seeing as many as 20 cases a day linked to synthetic substances.
However it said that has since decreased to about six cases a day over the weekend.