LISMORE solicitor and drug law reform expert Steve Bolt says motorists are being wrongly convicted of drug driving.
Mr Bolt, a partner at Bolt Findlay Solicitors in Lismore, said current laws allow people to be charged for having even miniscule traces of drugs in their system, despite being sober.
He believes drug driving laws need significant changes to prevent innocent people being caught up in the imprecise legislation.
It comes after the NRMA and the Police Association of NSW called for harsher sentencing for drug drivers recently in a press release, which Mr Bolt described as "not particularly focused".
"The issue is that the current testing regime does not measure impairment; it simply detects the presence of the drug in saliva," he said.
"This is an issue because cannabis, for example, can be detected for two days.
"We've had a number of clients who assured us, and it was accepted by the court, that they had taken the drugs more than 24 hours before they were tested."
Mr Bolt said laws on drug driving should closely mirror drink driving laws, which measure an acceptable level of intoxication.
He said if laws were reformed to set limits on intoxication, they would need to be accompanied by a system to measure it.
"Leaving aside that using the drugs is illegal, they're not being punished for taking cannabis or other drugs, but for driving with it in their system," he said.
"But there's no minimum level. In a lot of cases I've seen, police say there was no evidence of impairment.
"We need a legislative change that provides an allowable level of drugs for the purposes of driving and we need a device that's more accurate in detecting a limit of drugs."
Mr Bolt said without these changes people could, in theory, be convicted of little more than attending a party where cannabis smoke is present.
A number of Lismore magistrates have aired their concerns about current drug driving legislation during court cases this year.
The penalties for motorists caught with the active presence of cannabis, speed and ice and ecstasy in their system include an $1100 fine and a minimum three-month disqualification for a first time offence.
Heavier penalties apply for a second offence.