Researchers say their findings suggest there is no evidence that plain cigarette packs boost illicit tobacco trade as claimed by the tobacco industry.
Australia was the first country in the world to introduce standardised packaging for tobacco products in December 2012. New Zealand, Ireland, and the UK are currently considering similar legislation.
The researchers wanted to find out if the policy would deter people from buying their tobacco from small independent retailers, prompt a rise in the availability of cheap products sourced from Asia, and increase the use of illicitly traded tobacco, as predicted by the tobacco industry.
They therefore quizzed adult smokers on the phone about their tobacco purchasing habits a year before the plain packaging policy was introduced in 2011; during roll-out in 2012; and one year after implementation.
All participants were already taking part in an annual representative population survey about smoking and health in the Australian state of Victoria, which yielded around 4000 interviews in total for each of the years.
The researchers wanted to know if there had been any changes in the proportions of people buying from supermarkets rather than small independent retailers, and whether smokers had switched to very cheap cigarettes sourced from Asia or illicit unbranded tobacco.
In all, responses were received from just under 2000 smokers. They showed no change in the places smokers usually bought their tobacco from between 2011 and 2013.
Almost two thirds of respondents said they bought their tobacco from supermarkets in 2011 (65.4%) and in 2013 (65.7%). Similarly, there was no fall in the proportion who bought from small independent retailers: just over 9% said they bought their tobacco in these outlets in 2012 and just over 11% said they did so in 2013.
Use of low cost Asian brands was low, and scarcely changed between 2011, when it was 1.1%, and 2013, when it was 0.9%. And use of illicit unbranded tobacco didn't increase either: this was 2.3% in 2011, and 1.9% in 2013.
In 2013, just 2.6% of cigarette smokers said they had bought one or more packs that did not comply with the new regulationsand so may have been contraband within the preceding three months.
And 1.7% said they had bought from informal sources, such as a market stall or the back of a van, on one or more occasions over the past 12 months.
The researchers admit that the surveys were restricted to the State of Victoria where only a quarter of the population of Australia lives, so may not be applicable elsewhere. And any potential unintended consequences of the standardised packaging legislation should continue to be monitored, they say.
But they conclude: "In the meantime, this study provides no evidence of the unintended consequences of standardised packaging predicted by opponents [having] happened one year after implementation."