Alcohol interlocks were introduced in June last year, when the government accredited three providers to begin installing the devices in the vehicles of drink drivers.

The interlocks prevent a driver from starting the car until they provide a clean breath test. Offenders can only exit the program after demonstrating a period of clean driving, something reviewed by the Road Transport Authority.

Eighty-three interlocks have been fitted since the scheme began. Roughly half were voluntarily sought.

The scheme is designed to allow courts to issue restricted licences to help Canberrans keep their jobs, while maintaining confidence that they will not reoffend.

But lawyers with experience in acting for drink drivers say two issues have become problematic.

The first is the law's requirement for a mandatory delay for the worst offenders – habitual drink drivers and those with readings above .150 – between their conviction and the time they can obtain an interlock.

They must wait until serving half of their disqualification period before becoming eligible.

Lawyers say this is counterproductive, encouraging the worst drink drivers and those most likely to reoffend to get behind the wheel of another car while they wait for the interlock.

Paul Edmonds, of Canberra Criminal Lawyers, said there appeared to be little reason for the mandatory delay.

"If someone's getting a three or five year disqualification, that probably tells you straight away that's the sort of person who needs the interlock because they're a high-risk offender," he said.

"They're a recidivist if they've been disqualified for that long and they've probably got a drinking problem as well, and yet those people are having to wait between one and two years to get the interlock.

"I would definitely prefer that everyone who has a drink drive conviction be eligible for it upon being sentenced."

The second issue is the cost of installing the devices, which can be up to several thousand dollars for longer periods.

There are concessions for those on low-incomes, but many, including the ACT Council of Social Service, have argued they are insufficient.

Earlier this year, ACTCOSS urged the government to extend the concession as part of its broader submission on the need to bolster assistance to the most disadvantaged Canberrans.

Ben Aulich and Associates partner Peter Woodhouse said the cost of the alcohol interlocks was out of reach for some of those who were brought before the court.

"The availability of an interlock is a great way for somebody in dire need of their license to get back on the road as soon as possible."

"That comes at a price – several thousand dollars.

"Some people just cannot afford that."

Mr Woodhouse also argued against the need for offenders to serve half their disqualification period before becoming eligible for interlocks.

"I cannot see any justification for the requirement that they serve half of the disqualification time before they can get an interlock. The device eliminates the problem of drinking while intoxicated."