Experts say news of record haul of more than 11kg of the opioid drug, found in February, should have been announced sooner

The largest seizure of fentanyl in Australian history could signal that the potent opioid is about to be detected more regularly, drug experts say.

The Australian federal police announced on Monday a container that arrived in Melbourne last December held more than 11kg of pure powdered fentanyl and 30kg of methamphetamine.

The seizure represented more than 5m fentanyl doses, the AFP said, but it could not provide an estimate on the street value of the drug because there had been no precedent. Other fentanyl importations seized were all less than 30g.

Nobody has been charged in relation to the drugs, which were hidden in an industrial wooden lathe sent from Canada.

Fentanyl is a fast-acting opioid that is highly addictive and acts similarly to heroin. A single dose of 2mg can kill a person. The drug is primarily used for medical purposes in Australia but is an increasingly popular illicit drug overseas.

While Australian authorities have long braced for fentanyl’s impact, its use remains low.

The latest national wastewater drug monitoring program report found oxycodone and fentanyl use in Australia fluctuated but remained low and relatively stable, with regional consumption of fentanyl in December 2021 being the lowest level recorded.

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Prof Suzanne Nielsen, the deputy director of the Monash Addiction Research Centre at Monash University, said other local research supported these findings.

Nielsen and other researchers conducted more than 900 tests of urine samples taken from heroin users who visited supervised injecting centres in Melbourne and Sydney.

In findings released last year, it found only 1.9% of tests were positive for fentanyl.

But Nielsen said this did not mean that fentanyl, which had been responsible for thousands of overdose deaths in North America, could not rapidly emerge as a problem in Australia.

In North America, fentanyl was initially combined with heroin, resulting in an increase in overdoses. Eventually, the much stronger opioid was being demanded by the market instead of heroin.

“In a couple of months in some parts of North America, it went from seeing early signs of fentanyl to it being the dominant opioid in the market,” Nielsen said.

While heroin and fentanyl overdoses can be treated with the drug naloxone, Nielsen said fentanyl overdoses typically occurred far more quickly.

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She said ideally the AFP would have revealed the large importation, which it uncovered when the container was searched in February, far sooner, so those who researched drug use and worked in harm reduction services could be prepared.

“In an ideal world, when there are signs that we should be looking more carefully and monitoring more carefully for fentanyl, it would be good to know,” she said.

Sione Crawford, the chief executive officer of Harm Reduction Victoria, agreed. He also said the potential for heroin to be cut with fentanyl again highlighted the benefit in publicly funding illegal drug testing programs.

“It’s a concern that we didn’t know [about the seizure] for six months, because for the alcohol and other drugs and harm reduction sector to do its work, it’s useful to know what’s going around.

“People are going to keep dying from impure drugs, whether it’s MDMA … or heroin cut with fentanyl.

“Drug testing is just one tool in many that can reduce overdoses.”

The AFP have been contacted for comment.

In Australia, the National Alcohol and Other Drug Hotline is at 1800 250 015; families and friends can seek help at Family Drug Support Australia at 1300 368 186In the UK, Action on Addiction is available on 0300 330 0659. In the US, SAMHSA’s National Helpline is at 800-662-4357

This article was amended on 22 August 2022. A fatal dose of fentanyl is 2mg, not 28g as an earlier version said due to an error introduced during editing.

This article was amended on 24 August 2022. Sione Crawford is the chief executive officer of Harm Reduction Victoria, not Harm Reduction Australia as described in an earlier version.