Experts are warning there are deadlier versions of synthetic cannabis available in New Zealand which are much more potent than the one which caused the so-called zombie outbreaks in the US.
The Government's been told two deadly types of synthetic cannabis are so potent they should be classified as class A drugs.
One of these drugs has been linked to a well-known case that rocked the United States in 2016.
"The concentrations we're seeing in New Zealand are much more potent than what we saw in the Zombie outbreak in New York," Health Minister David Clark says.
In some instances, the drugs found here were 10 times stronger.
The news comes after synthetic cannabis was linked to the deaths of at least 45 people since June 2017.
"I don't think we ever anticipated we'd get new synthetic drugs that would lead to so much harm," Drug Foundation Executive Director Ross Bell told 1 NEWS.
Synthetic cannabis is already illegal - but the maximum punishment for dealers is two years in prison.
Making synthetic cannabis a class A drug would put it alongside methamphetamine, cocaine, magic mushrooms and lsd.
This would mean the police would have more power and the penalties would be significantly tougher for dealers and users.
The Government says it will make a decision on synthetic drugs in the coming weeks.