Government efforts regarding reducing car crashes where alcohol is a factor are focused on ensuring drivers comply with their legal limit, said a Ministry of Transport spokeswoman.
Initiatives have included introducing a zero breath alcohol concentration for drivers aged under 20 and repeat drink-drivers.
"We would reiterate that the law allows the police to require a driver, at any time, to undergo a breath test to see if they are complying with the legal limit,'' she said.
Road safety campaigner Clive Matthew-Wilson, who also edits car review website, dogandlemon.com, said he was shocked to learn the practice of driving with open bottles was legal and called for a law change.
"It's completely crazy. I just can't believe our lawmakers are that stupid,'' he said.
"It's like saying you're allowed to drive carrying a handgun as long as you're not shooting anyone.
"One tends to follow the other. If you're drinking while driving, then it's highly likely that it's going to cause serious road safety problems.''
Ministry of Transport figures showed drinking and driving killed 1463 people and injured 24,789 others in crashes on New Zealand roads between 2000 and 2011.
Nigel Hampton QC said motorists may not be breaking the law by drinking a beer while driving, but police could have "very good cause'' to pull them over.
"The cop would have every right to ask what they are doing and get them to `blow into this machine please','' he said.
