RoadSafe Northland Whangarei co-ordinator Gillian Archer said local people were becoming much less tolerant of drivers who got behind the wheel boozed.
"There's been a mood swing in the community to no longer accept drink-drivers because some people's lives are absolutely ruined by drink-drivers crashing into them, causing crashes or causing injury to themselves," she said.
The drop in convictions could also be attributed to "robust" policing, and the success of local alcohol programmes.
"[Northland police] are vigilant about catching drink-drivers, they're out there all the time, they're visible, there is an expectation [offenders] will be caught."
For those who were caught, programmes for both first-time drink-drivers and recidivist offenders showed success rates of up to 95 per cent, Mrs Archer said.
"There are psychological reasons people keep offending. They might not necessarily be alcoholics but they have attitudes and behaviours that can be changed."
In December last year, recidivist Whangarei drink-driver Louisa Johnson, 48, was jailed for 20 months after her sixth drink-driving charge.
Johnson blew 1388mcg, more than three times the legal limit.
A few months earlier, a 38-year-old man was taken to the Whangarei central police station by his wife after drink-driving home with their two young children in the car. He was breath-tested and allegedly recorded 752mcg.
And a Northland driver drove so drunk in 2010 his reading was off the scale.