Festival-goers looking to cap their day off by taking ecstasy are putting themselves "in a very risky situation", because they could be getting a new and much more potent drug instead.
That's the view of KnowYourStuffNZ, a community group that works in collaboration with the NZ Drug Foundation, which carries out a free drug-checking service at events across the country.
The organisation says a quarter of those trying to buy MDMA are actually being sold something else in its place - and if they are, it's usually N-ehylpentylone, a new drug that has exploded onto the NZ festival scene in recent years.
KnowYourStuffNZ says the drug was first spotted in the US in 2016, and has become increasingly prominent in New Zealand since its arrival here in early 2017. While it hasn't yet proven deadly on our shores, it has caused deaths overseas.
The group explains the drug is easy to sell in place of MDMA because it looks similar and produces some of the same effects.
"Users have described the experience as "seedy", "cracky", and much less pleasant [than MDMA]. Physical effects can include raised pulse and blood pressure, high body temperature, convulsions, acidosis, and rapid muscle breakdown," it said.
"Psychological effects include agitation, paranoia, compulsion to redose, difficulty sleeping for up to 36 hours, and temporary psychosis. As this drug is so new, little can be said about the health risks of long-term use."
KnowYourStuffNZ says while the effects are more serious with N-ethylpentylone than MDMA anyway, most of the risk lies in the fact it is much more potent, so it is "very easy to take too much".
"A common dose for MDMA is around 100 milligrams, whereas a dose for N-ethylpentylone can be as little as 30 milligrams," it said.
"If people believe they have MDMA and take 100 milligrams of N-ethylpentylone, then they are going to be in a very risky situation."
KnowYourStuffNZ recommends not taking N-ethylpentylone, and visiting its testing stations at events before taking any substances. More than half of those who discover what they bought isn't what they thought it was opt not to take it, it says.