The drug that killed more than 100,000 Americans last year is now thought to be behind 12 overdoses in Wairarapa.

Fentanyl has been described by the United Nations as one of the deadliest drugs.

The United Nations Office on Drugs and Crime released its annual World Drug Report in Vienna this week, estimating more than 100,000 people in the US died from a fentanyl overdose last year alone.

Now, experts here are calling for better prevention, before someone in New Zealand dies from the drug.

It is just the second time the drug has been found in New Zealand illicitly.

Five men and two women between 31 and 71 years old were admitted to Wairarapa Hospital, with another case thought to have gone directly to a Wellington hospital, says the DHB.

However, yesterday the drug information website High Alert says 12 people had been hospitalised due to suspected fentanyl overdoses over the weekend, all in the Wairarapa region.

Detective Inspector Blair Macdonald, from the National Drug Intelligence Bureau, says two people took the drug after buying what they thought was cocaine.

He says the bureau is still trying to find the supplier and how the drug got into the country.

"We are very, very aware that this drug will cause harm because it's highly active in such a small dose rate.

"Really just a few grains of salt is an active dose."

Drug-harm reduction organisation Know Your Stuff says fentanyl was first identified in New Zealand in 2018, when it was sold as heroin.

Managing director Wendy Allison says its re-appearance is not unexpected, and in the four years since, New Zealand has legalised drug checking and developed a national alert system for high-risk drugs.

However, she says it's concerning the synthetic is now being sold as cocaine because people are more likely to snort it, which might cause quicker overdoses, and possible deaths.

"We can't rule out the possibility that it's more widespread and [that] we will see further cases," she says.

"Even if we don't in this situation, fentanyl has now arrived on our shores and based on what we've seen overseas it's likely that we'll continue to see instances like this popping up."

The Needle Exchange Programme says its Masterton branch will hold a pop-up drug checking clinic on Thursday after the spate of overdoses.

They have also ordered in more fentanyl home test strips and Naloxone - a medicine used to reverse opioid overdose.

They have had a slew of enquiries since news of the weekend's overdoses broke.

National operations manager Philippa Jones says the incident shows the need for more permanent drug-checking services in places like Wairarapa.

"We've got 20 outlets around the country and quite a few of those outlets are in those more provincial areas," she says.

"We're a licensed drug checker, so we've got all the capability to actually do this and to have these facilities available but we just don't have any funding to actually make that happen."

Drug Foundation executive director Sarah Helm says these overdoses could have been avoided if New Zealand's 1975 drug laws had been updated.

She says the laws are based on the American system, which clearly is not working.

"One of the reasons we have this situation at all is because people are purchasing drugs on a black market, they are criminalised ... ," she says.

"We need to update our drug laws so we can use a health-based approach."

Helm says New Zealand also needs better resourcing for harm reduction and prevention initiatives, including funding to make Naloxone more accessible.

Deputy Prime Minister Grant Robertson says he's not aware of any concerns about the availability and supply of Naloxone.

Concern about possibility of more overdoses

Fentanyl arriving in New Zealand has been a case of 'when' rather than 'if', Drug Detection Agency chief operating officer Glenn Dobson told Checkpoint.

He says in its pure form a couple of grains is enough to kill someone.

There is a real concern there could be more fentanyl-related overdoses as it 's unclear how widespread the drug might be.

Dobson believes it will be unusual for it to be found in only one region of the country.

Asked how supplies would have reached Aotearoa, he says: "There's illegitimate labs in China and Mexico that produce it. DEA intel suggests India is another country emerging with illicit labs. From there generally the drugs will come through Canada, the US or Mexico, and make their way down to Australasia."

He reminds people that abstinence is the best safety mechanism.

-RNZ/Soumya Bhamidipati.