Illicit drug use is rampant in the West Coast workforce, with methamphetamine the drug of choice, according to recent tests.

The West Coast use of methamphetamine - nearly twice the national average - has alarmed the Drug Detection Agency.

Figures supplied by the agency yesterday show 23.8 per cent of workers drug tested on the West Coast last year had tested positive for methamphetamine use; the national average is 14.3 per cent.

Chief executive Kirk Hardy said it was the highest recorded in New Zealand.


"It is alarmingly high and is a concern, as is the high number of synthetic cannabis tests that came back positive," Mr Hardy said.

Synthetic cannabis showed up in 9.5 per cent of tests, again much higher than the national average of 3.8 per cent.

Mr Hardy noted that most of the testing took place in high-risk industries such as transport, forestry and heavy machinery operations.

Random drug testing was up slightly to 4.5 per cent from 4.2 per cent in 2013, with the national average of 5.3 per cent. Pre-employment tests were fairly static.

"Cause testing", where an employer suspected an employee may be under the influence, was particularly concerning, he said.

"There was a 100 per cent strike rate - which means every person suspected to be impaired, was."

Opiate use - morphine, heroine and over the counter drugs which contain codeine - showed a marked downturn from 38.1 per cent in 2013, to 9.5 per cent last year. Cannabis use was 66.7 per cent, below the national average of 76.5 per cent.

- The Greymouth Star