Judge David Robinson sentenced 41-year-old Angela Hamlin earlier this month on her third drink-driving charge, four years after she crashed and killed her teenage passenger in rural Southland.
During the hearing, he suggested the blood-alcohol limit should be reduced to 20mg of alcohol per litre of blood.
The current legal limit for over-20s is 50mg; the criminal limit is 80mg.
"The science tells us that really the only safe level of alcohol in your system is zero," Judge Robinson said.
"Right from the first drop you become impaired."
"It was an off-the-cuff comment to the defendant’s lawyer on some research he wanted the defendant to read," the spokesman said.
"It wasn’t in any way a statement against current legislation, which would be inappropriate."
Criminology emeritus professor Greg Newbold said decreasing the drink-driving limit further would have little effect.
"I don’t think it would have the impact some people think it will," he said.
"It’s just the wowsers stopping people from having a drink."
"The main thing that’s going to reduce people’s drink-driving is higher policing [levels], not lower limits."
Hamlin, whose driving ban had not long lapsed following the fatal crash, was sentenced to 150 hours’ community work and nine months’ supervision.
She is now subject to the alcohol-interlock licence regime.