Workplace cannabis detections have jumped nearly 8% nationwide, prompting fresh warnings for employers heading into the busy summer holiday season, according to new data from The Drug Detection Agency.
TDDA’s Q3 Imperans Report — the country’s largest snapshot of workplace drug and alcohol testing — shows cannabis remains the most common substance detected, appearing in 71.1% of all non-negative tests between July and September. Overall, 3.75% of screenings indicated the presence of drugs.
The agency says the rise is a concern as workplace Christmas functions approach, a period when drug and alcohol use traditionally increases.
TDDA chief executive Glenn Dobson says cocaine detections are also trending upward in parts of the country, including the North Shore, The Lakes, Canterbury and Tasman.
“Cocaine use has been steadily increasing over the year, and we believe that’s in no small part due to cartel activity,” Dobson says.
“Cocaine tends to be considered a more white-collar drug, and it has a seasonal pattern where usage tends to increase over the holidays. Corporate businesses have an increased awareness because they’re concerned, and rightly so, about the behaviour of their staff and their company’s reputation.”
While opioid positivity rates have stabilised at 18.6%, some regions are seeing sharp increases. Gisborne recorded a 41.7% rise in opioid detections during the quarter, prompting TDDA to advise employers to “take action now”.
Dobson says such spikes usually indicate easier access and higher supply.
“Cannabis has always been an issue for employers, but the data is telling us that use is very prevalent. Opioids saw modest declines in the regions, except for in Gisborne,” he says.
“A 50% surge in detections usually means there is easy access and abundant supply, that creates a risky climate for people conducting business.”
He says early signs of increased cocaine activity are also worrying.
“The early cocaine detections on the North Shore, The Lakes and in Canterbury are also concerning, cocaine is a serious drug and adversely affects performance.”
The agency says employers should take steps now to reinforce expectations ahead of end-of-year functions, where the line between socialising and workplace safety can blur.
TDDA recommends:
- reviewing and updating drug and alcohol policies
- reminding staff policies apply at events and on the way home
- offering education before Christmas functions
- training managers to recognise signs of drug use, including prescription misuse
- implementing regular and random testing
- considering return-to-work testing in January
“Reinforcing policies now can prevent difficult conversations or accidents,” Dobson says.
“Talking about return to work testing reminds people that safety doesn’t take the holidays off and everyone needs to come back to work fit for duty. It’s about balancing goodwill with responsibility.”
Drug trends at a glance
Comparing Q2 to Q3 2025, TDDA found:
- THC detections up 7.9%, now appearing in 71.1% of positive tests
- Amphetamine-type substances detections down 7.7%
- Opioids down 2.6%, but regional spikes persist
- Benzodiazepines down 2.5%
- Cocaine down slightly nationwide, but trending upward in multiple regions
Click here for the full Imperans Report.
