There are renewed warnings over the dangers of synthetic drugs as the Chief Coroner reveals they are responsible for up to 75 deaths.
An emergency department doctor says one puff can be fatal.
People being left paralysed by the so-called 'zombie drug' and shocking pictures dominated the headlines two years ago.
The shocking number of deaths caused by synthetic cannabis was released on Tuesday.
- More than 70 deaths blamed on synthetic drugs in two years
- Government announces major crackdown on synthetic drug dealers
- Two deaths from suspected bad batch of synthetic drugs in Christchurch
"What we had on the streets, especially in 2017 and 2018, were some of the strongest synthetic cannabis seen worldwide," says Dr Paul Quigley from the Wellington Hospital emergency department.
"The doses out there were enormous - one puff could kill."
Dr Quigley compares smoking the synthetic drug to playing a game of Russian roulette.
The Chief Coroner has confirmed that synthetic cannabis is responsible for 24 deaths, alongside a further 50 provisional cases. In the past two years, there has been a total of 70 to 75 deaths - and it's linked to even more.
"There are also a number of deaths where synthetic cannabis contributed [but] it was not the ultimate cause," says Judge Deborah Marshall.
Dr Quigley says it became deadly when it became illegal.
"When it's just made in your backyard and it's literally made in people's ovens and just sprayed on plant material on a bench you've got no idea what you're getting," he says.
And it's still a problem.
"Synthetics drugs are still being used on the street but they're also being used in homes, in the suburbs, in rural areas of New Zealand and small towns, so it is a problem across New Zealand," says Detective Inspector Scott Beard.
Beard wants help to catch those behind the manufacturing of synthetics.
"It's the people out in the community, who know who's manufacturing and supplying the drugs, that we need to contact us," he told Newshub.
Anyone using synthetic cannabis is urged to seek medical help.
A joint inquest is being planned to find ways to prevent further deaths.