A workplace drug testing company is sounding the alarm, with meth showing up disproportionately in results nationwide.

New data from the Drug Detection Agency finds meth's turned up in a quarter of all results.

It follows the Drug Trends Survey revealing gangs are behind one-in-three sales of methamphetamine across the country.

CEO Glenn Dobson says meth usage makes it harder for employees to do their work - and creates extra risks in the workplace.

"In general terms - it can affect them for about 48-72 hours. The thing with meth is that the user will go so hard and so long based on their lifestyle to stay up and stay active that they have a massive hangover effect afterwards when they come down."

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