Under the current law, police must have reasonable cause to suspect a driver is impaired by drugs and then they can require a behavioural test such as walking heel to toe in a straight line and turning and standing on one leg. If that test is failed, the driver can then be given a blood test.
But Transport Minister Phil Twyford said the proposed test would take between three and five minutes compared to the alcohol test of a few seconds.
On a busy highway that could mean dozens and dozens of vehicles stacked up on the side of a road waiting for the results and the actual percentage of people who would be picked up by random testing was likely to be very low.
Twyford said Police Minister Stuart Nash and Associate Transport Minister Julie Anne Genter were working on thee issue.
"We are confident…that they will come up with something that is comprehensive and effective, unlike this bill."
Mike Noon said the AA had hoped the bill could have progressed to a select committee so some of issues could be properly investigated.
Surveys of AA members over the past three years had showed 95 per cent support for introducing a saliva-based test to detect drugged driving.
Other countries, including Australia, Britain and Canada had introduced roadside saliva-screening tests to catch and deter drugged drivers.
"So it is possible if the will is there."
The Minister of Transport analysed the issue in 2016 and recommended a testing regime that would cost about $9 million annually and deliver an estimated $8 saving from reduced crashes for every $1 spent.
Family First has added its voice of support for roadside drug-testing of drivers, and called on the Government to change its mind and support the member's bill.
"We should take every measure possible to protect families and to reduce the road toll," said national director Bob McCoskrie.