A good proportion of those tested, up to 10 a week, are caught cheating.
That, together with a positive test rate of 8.5 per cent, suggests drug use among employees and job seekers for those businesses may be a bigger issue than many realise.
The Drug Detection Agency's Leigh Sefton says more local companies have recognised the benefits of drug testing, not just in terms of safety but also employee morale and productivity.
It's understandable that in industries like forestry, construction and trucking it's vital workers have their wits about them. Their own safety, and that of others around them, would be at risk otherwise.
But office workers would possibly feel a little less comfortable about the idea. Morale on testing day probably isn't the highest.
So it's important that businesses have a clear drug use policy that employees understand, and we're not just talking illegal drugs. Twelve per cent of positive tests were for over the counter medicines, prescription drugs or synthetic cannabis.
Provisional Department of Labour figures released yesterday show 41 people died in workplace incidents in 2011 (and that's not including road transport deaths). In a small country like this that's a shocking figure.
The increase in workplace testing shows more local businesses are getting serious about employee safety, and that's to be applauded.