Drug testing services have warned of the risk of synthetic opioids in Dunedin, following a death in Napier last week.
The death has been linked in the media to a notification by High Alert Drug Information and Alerts Aotearoa New Zealand.
The notification stated fake oxycodone tablets were found to have contained the substance metonitazene, a highly potent synthetic opioid, which was being sold online.
He said the widespread circulation of these pills was both possible and likely.
"The reality is this drug could potentially wind up in anything ... the potential for it to wind up in a more common party drug is entirely possible."
"That could most definitely happen in Dunedin and it could most definitely be a student or multiple."
Metonitazene had a similar potency to fentanyl, which was 100 times more potent than morphine, Mr Phillips said
While the problem of synthetic opioids was not strictly limited to Dunedin, Mr Phillips said it was relevant to the "perfect storm" of drug use in the city.
"Dunedin has a strong party culture, often resulting in the combination of drugs including but not limited to alcohol, MDMA, ketamine and a few others.
"This means that if misrepresented drugs were to circulate within Dunedin, that contained metonitazene, the outcomes would be dire.
"If it was to wind up being cut into someone’s MDMA, then Dunedin would definitely be a high-risk area."
NZ Needle Exchange Programme national harm reduction lead Jason George said they had detected a single case of metonitazene in Christchurch within the last week.
He confirmed this case was one of the fake oxycodone tablets available on the dark web, and the original listing of the tablets online had been updated to disclose it contained metonitazene.
With the pills circulating on the dark web, Mr George said they could appear anywhere in a matter of days.
"Anyone from any part of the country can order them and they’ll turn up in a courier package in a couple of days’ time.
"It’s very feasible they could be anywhere in New Zealand."
