Some New South Wales drivers will have breathalysers attached to their ignition systems in coming weeks, as the state rolls out its technological weapon in the fight for road safety.

NSW Transport says it will see the number of repeat drink drivers fall from the day mandatory ignition devices are introduced, which it says will happen within the year.

One state magistrate highlighted the need for the devices last week, lamenting the lack of options in sentencing a man caught drink driving three times in 24 hours, and later in the case of a father of six caught drink driving five times.

The NSW Centre for Road Safety says it may even enhance the scheme by making it harder for people to circumvent the devices, such as by having a sober person blow into the breathalyser.

Personal identification technology for the locks is being investigated.

“What we're working at is the smart systems that exist now that are about recognising that the person who is indeed blowing into that, is the driver and the person with the charge of having to use the alcohol interlock,” Centre for Road Safety General manager Marg Pendergarst has told the ABC.

“Basically to avoid the situation that your friend blows into it but you still drive home drunk.”

Ms Pendergast says the devices have become mandatory in certain cases from February this year.

“We're now driving to reach the group who continually drink drive - who either get busted twice in 5 years or indeed, go high range,” she said.

“They are the highest risk group and the most likely to be alcohol dependent.

“We are also looking within our package what rehabilitation we can put into the equation as well,” she said.