About 9800 people had charges for driving under the influence of drugs finalised in local courts last financial year, compared with 2300 the year prior, according to Bureau of Crime Statistics and Research analysis of court data released on Tuesday. That amounts to a rise of some 320 per cent.

"It seems likely that the increase in charges is a reflection of increased law enforcement activity rather than an increase in actual drug driving," the report concludes.

That follows a pledge in 2015 by Police Minister Troy Grant to triple the number of roadside drug tests conducted each year to 100,0000.

The crackdown effort has chiefly snared younger men and people from regional NSW, the analysis found.

The rate of convictions in regional NSW is roughly twice the state average. Only one metropolitan area, Sydney's outer-south-west is represented in the 10 parts of the state with the most convictions per capita.

The drug driving push has not been without controversy.

Critics note the law does not measure the point at which drivers are impaired by the presence of drugs in their system and argue drivers could be penalised for having fractional amounts of drugs in their system from consumption that took place long before testing.

Drivers have their saliva swabbed for three types of drugs: cannabis; amphetamines and methamphetamine or "ice"; and MDMA, an amphetamine derivative known commonly as "ecstasy".

Yet the machines used to test drivers' saliva could be used to detect cocaine and benzodiazepines but this functionality is not enabled.

Critics of the state's drug testing regime accuse the police of class bias for choosing not to select for those drugs.

A recent analysis also reportedly showed that tranquiliser-style benzodiazepines were the most common contributing factor to traffic accidents in NSW despite not being tested in roadside drug tests.

The crackdown has also greatly increased the risk of overrunning local courts, the report found.

Drug driving cases have risen to the 12th most commonly finalised matter in local courts each year from the 50th most common.

More than 98 per cent of people charged with offences are found guilty.

Men accounted for nearly eight in 10 drug driving convictions, with a slightly higher proportion of overall offenders aged under 45.

Convicted offenders have their licences suspended for a mandatory minimum period of six months for their first offence except in cases where a magistrate waives a conviction with a section 10 bond, as happens in about 30 per cent of cases.

About two-thirds of those convicted received a fine, of about $470, on average, for their first offence.