KnowYourStuffNZ director Wendy Allison said they began testing for fentanyl this summer after observing the rise in fentanyl use in other countries and becoming aware that it was being detected at the New Zealand border by Customs.
"We can't speculate about whether there is more in the market, but if we've found it is likely that there's more of it," she told Vice NZ.
"That seems to be the way these things go — that by the time we detect it, it's everywhere."
KnowYourStuffNZ had tested 418 drug samples at five events this festival season.
Opioid users should avoid and test for fentanyl, Allison said.
The most reliable testing method was using a fentanyl testing strip, which are available in New Zealand from the Hemp Store.
The drug has killed thousands of people in the United States, United Kingdom and Canada in the last two years through overdoses.
The death of popstar Prince in April 2016 was caused by fentanyl, sparking warnings from doctors about the drug.
Opioid addiction and abuse, including fentanyl, have become such a problem in America that President Donald Trump declared a public health emergency to combat the opioid crisis in October.
In the United States, 64,000 people died from drug overdoses in 2016, up 21 per cent on the previous year, the New York Times reported.
Fentanyl deaths were up 540 per cent in the past three years.
While the problem may not be as widespread in New Zealand, it is still an issue and new figures showed no slow down in the rate strong opioids were being prescribed by doctors around the country.
Prescription of strong opioids has continued to rise in New Zealand, with the use of fentanyl more than doubling, despite health experts warning of the dangers of the drug.
Data from the Health Quality and Safety Commission has shown the number of people who were prescribed a strong opioid (fentanyl, methadone, morphine, oxycodone or pethidine) at least once in a year had risen from 63,000 people in 2011 to 77,000 people in 2016.
Nationally, almost 17 people in every 1000 received a strong opioid, with most receiving morphine (11.2 per 1000). On average 1.8 people in every 1000 people received fentanyl – up from 0.77 in 2011.
The commission's figures showed 8368 people were prescribed fentanyl in 2016, with the figures steadily trending up from 3410 people in 2011.
Of the more than 8000 people prescribed fentanyl in 2016, almost 2000 were dispensed the drug for six weeks or more.
KnowYourStuffNZ is recommending a multi-agency, collaborative approach to dangerous emerging drugs.
"Agencies such as Customs, ESR, police, and emergency departments collect data on emerging drugs, but the information is not shared with the people most likely to be affected - the public of New Zealand," Allison said.
"We should not have to wait until there is a death from inadvertent fentanyl ingestion for an Early Warning System to be a priority."
The Misuse of Drugs Act needed to empower district health boards and other drug health services to provide forensic drug checking, and emergency overdose kits containing naloxone, an antidote to opioid overdose, should be distributed to users of opioid drugs and their loved ones, she said.
"Most overdoses happen in front of other people and deaths are avoidable if naloxone is readily available."
Fentanyl
• A fentanyl high is similar to heroin providing reduced feelings of pain, euphoria and relaxation.
• Respiratory failure is the most common cause of death in those taking the drug.
• It is usually administered using a patch. One patch lasts about three days.
