Up to a quarter of construction workers on some Christchurch building sites are failing drug tests while 7.5 per cent of those in the construction sector in Canterbury are also failing.
Karen Woolf works as a clinical nurse for Triex, the company that conducts drug tests on workers at construction sites across the region.
Ms Woolf told One News as much as 20 to 25 per cent of tests were now coming back as non-negative.
She told One News that while cannabinoids were usually the reason workers failed these tests, an increasing amount were now failing due to the use of methamphetamines.
Ms Woolf said one year ago, barely one worker would fail these test because of the use of methamphetamine.
