The Police Association says officers' workloads are big enough without enforcing smoking and vaping bans.
Newstalk ZB has revealed in the four years since a law banning smoking and vaping in cars with children was passed, no one has been fined or summonsed to court.
Association President Chris Cahill says there are much more important things for police to focus on.
He told Mike Hosking police are damned if they do and damned if they don't.
Cahill believes as soon as police start enforcing fines, there would be immediate questions about equity and whether the fines were given out fairly.
He said officers already have to deal with breath testing, retail crime, beat work and fighting the gangs.
LISTEN ABOVE

Mark the Week: 'Horse-faced duck' gave a look behind the scenes at Labour
02:48

Mike's Minute: My thoughts on the Budget
01:59

Richard Arnold: US Correspondent on the latest draft plan for an extension to the ceasefire between Iran and the US
03:14