Use of amphetamines prevalent in the Bay

One in five Bay employees who test positive for drugs is taking amphetamine-type substances, such as methamphetamine.

This is 50 per cent higher than nationally.

New Zealand Drug Detection Agency figures show of the 401 Bay employees who tested positive for drugs last financial year, 21 per cent, or 84, had amphetamine-type substances in their system.

Nationally the figure was 14 per cent.

Detection Agency Bay of Plenty general manager Leigh Sefton said the high incidence in the Bay was concerning.

"That's really high for that particular drug type," Mr Sefton said.

"That's 84 people on the road on meth driving at you, and that's only those from the workplace."

Erratic and aggressive behaviour made methamphetamine users a danger in the workplace.

"You get both ends of the spectrum ... you get a mirror image low of the high. One minute they're depressed, the next minute they can't stop talking. The following day they are at home contemplating suicide," he said.

"You put someone like that on any type of machinery and they will be the people who don't listen to speed restrictions. They take the risk, they jump from somewhere because they think they can. They do all sorts of stupid things. The drug makes them invincible."

Their expensive habit could also make them more likely to steal from their employers, Mr Sefton said. The agency carried out testing in a range of industries, from white collar workers to those in forestry and transport.

Mr Sefton did not know why the use of amphetamines was so prevalent in the Bay: "It's a really hard one to put your finger on. There are a lot of factors in there."

But he said employers should be proactive, rather than reactive, in tackling the problem.

All staff should be educated about the dangers of drugs in the workplace and potential employees should be drug tested as part of their job application.

"Screen them before you even take them on," he said. While drug use presented differently in different people, signs to watch out for were erratic behaviour and repeat incidents or accidents that shouldn't be happening.

Nationally, the incidence of amphetamine use amongst those who tested positive for drug use in the workplace has risen from 11.3 per cent to 14.4 per cent.

While Mr Sefton did not have a comparative figure for the Bay of Plenty, he said it had likely risen here also: "If it jumped 3 per cent nationally we've obviously jumped up as well."

Overall the most-detected drug was THC, the active ingredient in cannabis, showing up in 67 per cent of those Bay workers who tested positive for drug use - slightly lower than the 69 per cent nationally.

Ten per cent tested positive for opiates, such as codeine, morphine and heroin, compared to 16 per cent nationally and 2 per cent for benzodiazepines (sleeping pills, anti-depressants and sedatives) compared to 1 per cent nationally. Zero per cent tested positive for cocaine regionally or nationally.