New evidence shows one in five children continue to be exposed to smoking in cars.

The research, led by the University of Otago, Wellington, and published in the New Zealand Medical Journal recently, analysed trends in children's second hand smoke exposure in cars.

The surveys were conducted between 2006 and 2015 and included between 19,000 and 29,500 students who were asked whether, in the past week, others had smoked around them in a car or van.

Professor Richard Edwards, co-director of the research collaboration, says his team's analysis shows that exposure of children to smoking in cars is unacceptably high and actually increased in 2015 with close to one third of Maori students and over a quarter of Pacific students reporting being in a car with someone smoking in the past week.

"If the levels of exposure reported in 2015 in the survey applied to all Year 10 students, we estimate that almost 12,000 14-15 year-olds were exposed to smoking in cars each week in that year.”

In October 2015 a petition presented to parliament by Smokefree Northland prompted a Health Select Committee investigation and subsequent recommendation that the government introduce legislation or other measures to ban smoking in cars carrying children under the age of 18 years.

The government rejected the recommendation on the grounds that "present initiatives are sufficient to deter smoking in cars carrying children under the age of 18 years".

Richard says levels of second-hand smoke in cars is a severe health hazard for children. 'Many countries, including the UK and states and provinces in Australia, Canada and America, have introduced legislation to prohibit smoking in cars where children are present. So, New Zealand is falling well short of international best practice on protecting children from this completely avoidable harm."

The health effects of second-hand smoke for children include increased risk of respiratory tract infections, exacerbations of asthma and ‘glue ear'.