"Data collected by police over the past 22 months shows 53 drivers were involved in fatal and serious injury crashes with blood alcohol readings of between 51 and 80 milligrams per 100 millilitres of blood,'' Mr Brownlee said.
Under the changes, the penalty for returning a positive test between 50mg and 80mg would be a $200 fine and 50 demerit points.
Testing positive to more than 80mg would remain a criminal offence.
"We know that drivers with a very high blood alcohol concentration, and recidivist drink drivers, are responsible for a much higher proportion of alcohol-related road fatalities. That is why we believe this fine-based approach at the lower end is most appropriate,'' Mr Brownlee said.
The change will bring New Zealand into line with Australia's legal alcohol limit of 50mg per 100ml of blood.