INTRODUCTION

Illicit tobacco poses a significant challenge to public health efforts. New Zealand (NZ) stands out for its stringent tobacco control policies, but there are concerns that the size of the illicit market could grow. Estimating the extent of the illicit tobacco trade in NZ remains challenging due to the diverse methodologies used by various stakeholders over different years.

METHODS

We did annual consumption gap analyses (CGA) from 2012 to 2023 by calculating the discrepancy between estimated cigarette smoking (factory-made cigarettes and roll-your-own cigarettes) and legal sales to examine trends in the illicit tobacco trade in NZ.

RESULTS

The proportion of illicit tobacco in the NZ market fluctuated between 2012 and 2023. The negative test statistic of Kendall's tau indicates a slightly downward trend, but the trend is weak and statistically insignificant. The negative percentage may reflect under-reporting or the absence of hidden populations' consumption estimates, or the overestimation of legal sales. Our analyses adjust for under-reporting of smoking by using an uplift factor of 1.23 and adopt a 'worst-case scenario' by using the upper limit of the 95% CI around the point estimate for the proportion of daily smokers.

CONCLUSION

CGA is a useful tool for estimating the illicit tobacco trade, but it depends on accurate and valid estimates of consumption, under-reporting and reporting of legal tobacco supply. It is most useful to estimate the trend rather than the absolute amount of illicit tobacco. In NZ, the estimated proportion of illicit tobacco fluctuated between 2012 and 2023, supported by the statistically insignificant Mann-Kendall test. Reducing demand for smoking, alongside more vigorous border scrutiny and enforcement, is the most effective strategy for tackling the illicit trade. NZ's Smokefree aspirations to see prevalence drop to 5% or lower in the next few years may, therefore, significantly reduce the size of the illicit tobacco market.