Cannabis is still the most common drug ''by a country mile'' found when staff are tested, farmers attending a workshop in Ashburton last week heard.
Therese Gibbens, general manager of the Canterbury West Coast area for The Drug Detection Agency, said 80% of positive drug results from tests carried out by the company in Canterbury detected cannabis.
This was followed by opiates, amphetamines and methamphetamine. She had tips for farmers about policies, detection and managing the risks of staff affected by drugs or alcohol, backed up by statistics and experience.
The workshop was one of five being jointly hosted by Federated Farmers, the agency and rural insurer FMG, to raise vigilance around suspected drug use and manufacture. In Canterbury, 4% of people tested before they were employed failed drug tests. This rose to 34% when workers were tested because employers suspected they were affected by drugs.
A random drug test in Canterbury showed 5% of people failed the test, but this rose to 6.3% if a test was conducted following an accident or incident. The farming sector was one of the agency's biggest growth areas for testing, Ms Gibbens said.