A Wairarapa meat processing company is protecting workers from serious injury with a random drug testing policy designed to weed out employees under the influence of legal highs or illicit drugs.
It comes as the number of workplace drug tests surge nationwide.
Carterton's Cabernet Foods director Lyndon Everton said the recruitment company they used to hire staff had a pre-employment drug testing policy.
The meat processing company also carried out random, workplace drug testing, which had previously caught out an employee using synthetic cannabis, Mr Everton said.
"They just come up through the screening process and we send them away to be rehabilitated and then they have to have three clear tests within a six-month period."
The employee did not work in a "safety sensitive" area and was now back working with the company, Mr Everton said.
New Zealand Drug Detection Agency (NZDDA) testing stats show 3270 workplace drug tests were conducted in the Wellington region last year, of which 6 per cent were "non-negative".
Cannabis continued to be the most frequent drug detected - showing up in 71 per cent of non-negative tests nationwide last year.
Opiates (including codeine), methamphetamine, amphetamine, cocaine and benzodiazepines were also detected.
The agency conducted 68,561 on-site drug screening tests in 2012, up 31 per cent from 2011.
The testing was predominantly carried out in safety-sensitive industries, including construction, forestry, freezing works, manufacturing, mining, oil and gas, transport and waste collection.
Cannabis use was most common amongst forestry and construction workers, while methamphetamine was found predominantly in mining and oil and gas industries.
Regional trends showed traditional cannabis growing areas Northland, Bay of Plenty and the East Coast had high cannabis usage - as did Wellington.
The other obvious regional trend was opiate (most likely codeine) abuse in the South Island.
NZDDA chief executive Chris Hilson said since late 2012, 15 per cent of all workplace drug screening was for synthetic cannabis, with the figure expected to rise.
Synthetic cannabinoids could be detectable in a person's system for up to 102 days, Mr Hilson said. This meant some employees still had the drugs in the systems on the job, many in safety-sensitive industries.
"It's not just the accidents that can happen that can affect the drug user, but the usage may result in injury to nearby colleagues, customers and suppliers, and in some cases the general public."
About 6.4 per cent of last year's tests were 'non-negative' - indicating the presence of a drug. Samples are then sent to a laboratory for confirmation.
The 2012 non-negative results were down slightly from 2011, when 7 per cent of on-site tests detected drug use.
New Zealand Council of Trade Unions (CTU) spokesman Jeff Sissons said the union condemned drug use if it put workers or the public at risk.
"A good drug testing policy may be fair enough in a safety-sensitive workplace, but a lot of the rise in drug testing we think is occurring in non safety-sensitive workplaces."
Health and safety requirements had to be weighed against invasion of privacy. Workers in office jobs in safety-sensitive industries should not be subject to random drug tests, as their role was not safety-sensitive, Mr Sissons said.
Last year 89 per cent of workers tested were men, and 11 per cent women.
While testing occurred pre-employment, random workplace testing was also common.
Workplace drug tests in 2011:
2963 in Wellington region, 8 per cent non-negative
52,124 nationwide, 7 per cent non-negative
Workplace drug tests in 2012:
3270 in Wellington region, 6 per cent non-negative
68,561 nationwide, 6.4 per cent non-negative