The AA is backing a bill which would let Police conduct random roadside drug tests

The new law would allow oral fluid tests for the most prevalent drugs used by drivers - including cannabis, P, cocaine and MDMA.

Those caught would be fined, suspended from driving for 12 hours, gain demerit points - and could face harsher penalties.

Road safety spokesman Dylan Thomsen says it's a good move.

He says the Government's proposal has a well balanced system, and that the accuracy of drug testing devices is usually around 90 percent.