Exposure to second-hand tobacco smoke in cars remains a health hazard for thousands of New Zealand children, particularly Māori and Pasikifa, according to an Otago University study.
The authors say the findings show the Government's assertion that current initiatives are sufficient to protect children is clearly incorrect.
They have called on the Government to introduce smokefree cars legislation to protect against second-hand smoke and to help to reduce inequalities in child health.
The study, published in the NZ Medical Journal, involved analysis of Action on Smoking and Health (ASH) surveys of year 10 students from 2006 to 2015.
Between 19,000 and 29,000 students each year were asked if someone had smoked around them in a car or van in the previous week.
The results indicate that, while the overall proportion of children who answered yes had dropped from 30 percent since 2006, the decline has stalled.
Since 2012, the figure has hovered around 20 percent.
Exposure was consistently greater among Māori and Pasikifa students - at 32 percent and 26 percent respectively in 2015 - and it was particularly prevalent among those in lower decile schools.