Northland road policing manager Inspector Murray Hodson said the lower limit will force Kiwis to address their drinking patterns.
"It's difficult to gauge what will happen initially," he said. "Over the last year we have seen a decrease in the number of apprehensions for drink driving in Northland but a lowering of the breath and blood alcohol limit will mean a society mindset change in how they go about their patterns.
"There will be some who may not adjust their drinking patterns."
The lower limit was a key strategy to reduce serious injury crashes, Mr Hodson said. "I would like to think that the societal mindset has already shifted to one where drinking and driving is unacceptable. But having said that, there are still a number of recidivist drink drivers who are being apprehended throughout the last 12 months and that is a concern."
Under the new limit, drivers caught between 251mcg and 400mcg will receive an instant $200 fine, 50 demerit points and a ban from driving for 12 hours but no criminal conviction.
Driving with more than 400 mcg breath/alcohol remains a criminal offence. The limit for drivers under 20 remains at zero.
Kawakawa's Klondike Ale House manager Maria Van Eyk said she was concerned the wrong people were being targeted.
"I think it wouldn't matter whether it's a zero tolerance scenario, it won't catch the recidivist offenders, the ones that will just drink anyway.
"It's really targeting the people that do a hard day's yakka and then stop for a couple of beers on the way home.
"It's going to affect everybody in the hospitality industry but now it is a case of refocusing on food, and low-strength beverages."
Northland branch president of Hospitality NZ, Phil Sentch, owner of Rynoz and the Tote and Poke Sportsbar in Whangarei, said the industry was fairly relaxed about the change and not anticipating a big impact on business.
Most people who drank in bars arranged sober drivers or alternative transport, Mr Sentch said. The industry had learned to refocus on food and host responsibility and his own bar, for example, sold a wide range of low-alcohol or non-alcoholic drinks, he said.
