Drug testing at seven festivals over the summer has identified more new psychoactive substances than ever before.
"We have seen more MDMA, and more of it has been real," said KnowYourStuffNZ director Wendy Allison.
"We have also seen pills containing very high doses of MDMA, n-ethylpentylone sold as MDMA, and several new substances - a few of which we couldn't identify. These all have the potential to be very dangerous."
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KnowYourStuffNZ and the NZ Drug foundation tested 445 illicit drug samples over summer.
The overall percentage of drugs that were 'as presumed' increased from 68% to 79%, mostly because of an increase in quality of genuine MDMA and a higher proportion of MDMA among the samples.
The tests identified 44 different psychoactive substances in the samples. Forty percent of samples that were not as presumed were cathinones or 'bath salts' and one third of these were n-ethylpentylone.
N-ethylpentylone is the drug that hospitalised 13 people in Christchurch in February, after they inadvertently took it at a party.
"This season, KnowYourStuffNZ's testing prevented several other groups from taking n-ethylpentylone that they thought was MDMA," said Ms Allison.
"The Christchurch hospitalisations may have been prevented if those people had access to drug checking."
NZ Drug Foundation executive director Ross Bell said: "These results strengthen the case for essential drug checking services to be provided at more festivals, events and clubs, and highlight the urgent need for the government to establish its Early Warning System for drugs and to incorporate drug checking services into that system."
When a sample was not as presumed, 58% of people said they would not take it.
"When you give people accurate information about drugs, they make better choices. And for a lot of people, drug checking is the first time they have had access to comprehensive and factual information," Ms Allison said.