"I think probably the biggest factor in terms of the reduction in youth smoking has been the recent tax increases. The tax on cigarettes has increased by about 30 per cent over the last 18 months, and I think that's had a huge impact because young smokers are especially sensitive to how much cigarettes cost."
Society's perception around buying and smoking cigarettes was changing, with more communities and councils discussing smokefree zones, he said.
"We're getting more and more quit attempts by adults as well. The environment in which these young people are growing up and the way in which they are being exposed to tobacco and the risk factors around smoking is also undergoing a change, and I think that's influence which is trickling down to their behaviour.
"The rates in which smoking is going down....are quite indicative that perhaps smoking is not as cool as it was, it's not being considered as an expression of being grown up and independent, but actually being independent is being able to make strong choices not to start smoking in the first place."
He said 14- and 15-year-olds were surveyed because that was the average age at which New Zealanders picked up the habit.
"Almost every single smoker has started before they were 18. So surveying this age group is really important in terms of understanding about young people taking up smoking, the reasons they take up smoking, and helping us implement policies and campaigns which are going to help prevent them from starting in the first place."
Maori youth remained the largest smoking group, with 18 per cent of Maori youths surveyed classified as a regular smoker.
Mr Youdan said this group had traditionally had higher smoking levels because of "historical reasons".
"Going right back to the fact that commercial tobacco companies had targeted Maori with smoking for as long as they've been operating in New Zealand, and particularly Maori women. The positive thing here is that we're seeing the biggest decline in smoking rates amongst Maori young people, and that inequalities gap is closing now."
Smoking also remained more popular among girls than boys, with 9.3 per cent of girls surveyed regular smokers compared to 7 per cent of boys.
This year's survey would hopefully provide information for a campaign to have plain packets for cigarettes, he said.
Mr Youdan said the next survey would measure the impact that the disappearance of retail cigarette displays would have on smoking levels.
From July, cigarette companies are no longer allowed to have tobacco displays in shops.
