A controversial plan by global mining manufacturer Caterpillar (Cat) to force workers to use a urine-based drug and alcohol test at its Burnie site in Tasmania, is "outdated and inaccurate" says the AMWU.

AMWU Tasmanian President, Shane Littler, said the workers at Cat did not oppose drug testing in principle, but the method proposed by the company was more focused on controlling the lifestyle of workers outside of work – rather than the workplace.

He said better technology was available, and was the standard used at many workplaces.

"Tasmania Police, other mainland forces as well as many large Tasmanian companies are using saliva tests, not urine tests," Mr Littler said.

“Our concern with Cat management’s proposed method of testing is outdated, messy and can give false readings."

Mr Littler said the saliva test method was faster, more accurate and less invasive.

The AMWU will continue to negotiate with Cat management in an effort to use saliva tests instead.

“If a saliva method of testing is OK for the Tasmanian police and other Tasmanian companies why is it not ok for a large American company?”

The Burnie site, which designs, constructs and distributes underground mine machinery employs around 50 AMWU members primarily working in metal trades.