Police have carried out nearly half a million fewer breath tests in the last year. Auckland had the greatest drop in the number of tests, falling 42 per cent to 82,757.
Road policing national operations manager Inspector Peter McKennie said the overall drop was a reflection of police being "a little bit smarter about how we do things".
Police were competing with Facebook pages and group text messages that exposed the location of checkpoints within minutes.
Police may target certain events or "known hotels, sports clubs . . . which don't necessarily get the high level of breath tests but are still very strategic in terms of preventing alcohol harm on the road", he said.
"We know that some people drink and drive and take risks on the premise that they know where police set up high volume checkpoints and take alternate routes."
The law change introduced last December, where drivers received an instant fine for breath alcohol readings from 251mcg/L to 400mcg/L, had a "profound effect" on drinking culture and drink driving, as more people planned how they would get home after a night out,.