Super-strong synthetic drugs made by "idiot dealers and manufacturers" were responsible for the spike in deaths linked to the substances, an emergency doctor says.
The death of a man in Hutt Valley last night has been linked by the police to synthetic drugs, adding to the 20 already suspected to be caused by the substances.
Police said this afternoon that there have been 17 "incidents" related to the drugs in the Kapiti-Mana area in last 10 days alone.
Paul Quigley is an emergency medicine specialist and clinical toxicologist at Wellington Hospital.
He told Checkpoint "idiot dealers and manufacturers" did not understand the chemicals they were using and were making batches that were "way too strong".
"They basically cause this havoc that does last for these short spells - perhaps a week or less, with terrible damage to the community in the process - and then it goes away.
"The user thinks they are just having a bong or a single puff, but what they are getting is this massive overdose."
Dr Quigley said the drugs could cause seizure and irregular heartbeat leading to death, and they were also highly addictive.
Work needed to be done to find out why users - which were dominated by Māori and Pacifica people - were continuing to take the drug, he said.