The numbers are no longer subtle
New Zealand’s workplace opioid problem has shifted from background noise to a measurable operational risk in the space of two years. Data from The Drug Detection Agency (TDDA), which conducts more than 250,000 workplace tests annually, shows opioids appeared in 18.6% of positive tests in Q4 2025, up from 11.9% in Q4 2023. That’s a 54% relative increase.
Cannabis still dominates at 67.5% of positive results, but its share is declining. Opioids and amphetamines are filling the gap. The overall detection rate across all screens hit 4.01% in Q4 2025, meaning roughly one in 25 workers tested is returning a positive result for something.
For construction, transport, manufacturing, and agriculture, this is not an HR inconvenience. TDDA CEO Glenn Dobson put it plainly: “In high-risk environments like construction, transport, and manufacturing, impairment can be the difference between a routine workday and a fatal incident.”
Regional variation tells you where the supply chains run
The national average masks sharp regional spikes. Otago saw opioid detections jump from 28.1% to 36.4% of positive tests in a single quarter. Taranaki, Tasman, and Wellington also recorded sharp increases in Q4 2025.
Dobson attributes this to distribution dynamics. “They may start with a kilo of cocaine, but as it goes through various hands, it gets stepped on each time or gets mixed with fillers,” he told the Otago Daily Times. Different regions face different risk profiles depending on which supply networks reach them.
Cocaine detections nationally jumped 148% from Q3 to Q4 2025, concentrated in Auckland West, Bay of Plenty, and Waikato. The NZ Police wastewater programme independently confirms cocaine consumption running 8% above its four-quarter average.
Prescription medications make this harder than “fire and move on”
A critical complication: opioid detections include legally prescribed medications used above testing thresholds. Dobson acknowledged the nuance: “Opioids also include prescription medications, but often it’s around prescription medications that may be used above a certain cut-off, so it can create a potential safety risk within the workplace.”
This means employers cannot simply treat every positive opioid test as grounds for dismissal. Policies need frameworks for prescription disclosure without automatic punitive consequences. Most do not have them.
The fentanyl signal nobody wants to hear
Dobson has flagged synthetic opioids entering New Zealand’s supply through contamination of other drugs. “We have seen synthetic opioids like fentanyl being put in other drugs to either give the drug user a different high or to give them an addiction so that they keep going back to that drug dealer,” he said. This is not hypothetical American scaremongering. Police wastewater testing now specifically screens for fentanyl and heroin across sites covering approximately 77% of the population.
Most businesses know they have a problem but haven’t done anything about it
A TDDA survey of over 1,000 businesses found 22% had not reviewed their drug and alcohol policy in the past 12 months. Only 58% conducted regular occupational health checks. A full 20% provided no staff training on drug policies whatsoever. While 45% identified opioids as a concern, Dobson’s assessment is blunt: “Strong intent is not matched by operational certainty, creating avoidable legal, safety and productivity exposure.”
The drug landscape has moved faster than most policies. “It wasn’t long ago businesses were mostly worried about cannabis and methamphetamine, but the global drug trade and cartel activity have brought more risk to New Zealand’s shores,” Dobson said.
Federated Farmers board member David Birkett has urged farmers to incorporate drug testing into health and safety plans, reflecting that the risk extends well beyond urban workplaces.
The legal exposure is already here
The Health and Safety at Work Act 2015 places a primary duty of care on employers to manage foreseeable hazards. With opioid impairment now appearing in nearly one in five positive workplace tests, across a quarter-million annual screens, it is difficult to argue the risk is not foreseeable. Employers in safety-critical sectors who have not updated their policies to address opioids, prescription medication frameworks, and synthetic cannabinoids are carrying a liability they could eliminate with a policy review and a training session. The data is clear. The question is how many employers will act before an incident forces them to.
Sources
- TDDA: New Zealand Imperans Q4 2025 Report, State of Workplace Drug Use
- National Road Carriers: Imperans Q4 2025 Report, State of Workplace Drug Use from TDDA
- TDDA: Imperans Q4 2024 Report, State of Workplace Drug Use
- Otago Daily Times: Use of opioids rising in Otago, survey finds
- Safety News: State of Workplace Drug Use (Q4 2024)
- Otago Daily Times: Concerns grow over workplace drug use
- NZ Police: National Drugs in Wastewater Testing Programme – Quarter 2, 2025
- Safety News: Most recognise drug problem but unsure of the solution
- Farmers Weekly: Uptick in opioid use found in workplace drug testing