Researchers are calling for Australian-style restrictions on outdoor smoking at bars, cafes and restaurants, after finding high levels of air pollution, and that much of it drifts inside.
The smoke tests by Otago University researchers around Wellington found the highest levels of fine-particle pollution were in the partially enclosed outdoor smoking areas of hospitality venues - on average 72 micrograms per cubic metre of air.
But the levels were also high - 54 micrograms per cubic metre - inside bars in areas next to to the outdoor smoking areas.
Areas further inside bars and restaurants had much lower levels.
"This suggests there is smoke drift from secondhand smoke in the outdoor smoking areas to the inside," Nick Wilson and colleagues write in the latest NZ Medical Journal.
They urge extending statutory smokefree areas to cover half of seated outdoor areas of hospitality venues, as is done in in parts of Canada, the US and Australia.
"This could be justified on grounds of protecting workers' health and fairness to non-smokers - allowing some reasonable access to semi-smokefree outdoor seating - and is likely to have high public political acceptability."
But the paper adds that banning smoking in cars carrying children - an idea supported by Associate Health Minister Tariana Turia - "is probably the priority new smokefree law required in New Zealand".
The concentration of fine-particle pollution from tobacco smoke can be 51 times greater inside a car with the windows closed than the levels measured outside bars.
There is near universal support for this policy, even among smokers, although not among policymakers.
Policymakers were "considerably" out of step with the public over smoking in cars, said Otago University researcher George Thomson, after publishing a related study.
Sixty-two policymakers - district health board members and current and past MPs and senior officials - were interviewed for his study about prohibiting smoking to protect children at home, in cars and in parks.
"Most interviewees deferred to a smoker's right to smoke [at home], rather than the protection of children from secondhand smoke." Dr Thomson and colleagues say in the journal BMC Public Health.
This is despite the estimated effects of secondhand smoke on children including 50 deaths a year and thousands of cases of illness, largely from exposure in homes and cars.
The interviewees believed the home was private, where people's actions were their own business.
Many viewed cars as similarly private places regarding smoking, but public regarding traffic safety matters like policing of seatbelt use.
There was more support for smokefree policies in parks, but many interviewees considered outright bans too drastic.
* Inside workplaces - banned.
* Outdoors at pubs, cafes, restaurants - restricted.
* Patrolled areas of beaches and within 10m of outdoor playground equipment - banned.
* Within 4m of non-residential building entrances - banned.
* In cars carrying a child - banned.
* Inside workplaces - banned.
* Outside at pubs, cafes, restaurants - permitted.
* Beaches and playgrounds - permitted, but actively discouraged by a third of councils.
* Near building entrances - permitted on public streets, otherwise up to property owner.