A cheap drug 50 times more potent than heroin is being imported by drug traffickers into New Zealand, an expert says.
Fentanyl emerged in New Zealand for the first time at a music festival in February. The drug is particularly deadly and just three milligrams is enough to cause a fatal overdose.
Massey University senior drug researcher Chris Wilkins told The AM Show this morning the drug has caused a lot of overdoses in North America and Canada.
He said the problem in New Zealand is traffickers have been lacing the powerful opioid with heroin.
"The [heroin] users don't know that's happening and they get a much larger dose than they expect," Mr Wilkins said.
"Because it's so powerful then getting the right dose is really critical and your average drug trafficker can't get that right and that's why it's so dangerous."
The drug was appealing to traffickers because it was cheap and easy to smuggle, Mr Wilkins said.
In the last two years Fentanyl has killed a significant number of people in the United States, United Kingdom and Canada and was a key cause in the deaths of superstars Michael Jackson, Prince and Tom Petty.