Objective To determine whether smokers smoking from packs required under Australia's plain packaging law had different smoking beliefs and quitting thoughts, compared with those still smoking from branded packs.

Design Cross-sectional survey during the roll-out phase of the law, analysed by timing of survey.

Setting Australian state of Victoria, November 2012.

Participants 536 cigarette smokers with a usual brand, of whom 72.3% were smoking from a plain pack and 27.7% were smoking from a branded pack.

Primary outcome measures Perceived quality and satisfaction of cigarettes compared with 1 year ago, frequency of thoughts of smoking harm, perceived exaggeration of harms, frequency of thoughts of quitting, quitting priority in life, intention to quit, approval of large graphic health warnings and plain packaging.

Results Compared with branded pack smokers, those smoking from plain packs perceived their cigarettes to be lower in quality (adjusted OR (AdjOR)=1.66, p=0.045), tended to perceive their cigarettes as less satisfying than a year ago (AdjOR=1.70, p=0.052), were more likely to have thought about quitting at least once a day in the past week (AdjOR=1.81, p=0.013) and to rate quitting as a higher priority in their lives (F=13.11, df=1, p<0.001). Plain pack smokers were more likely to support the policy than branded pack smokers (AdjOR=1.51, p=0.049). Branded and plain pack smokers did not differ on measures of less immediate smoking intentions, frequency of thoughts about harms or perceived exaggeration of harms. Appeal outcomes, but not other outcomes, were sensitive to the extent of roll-out, with responses from branded pack smokers approaching those of plain pack smokers, once 80% of survey respondents were smoking from plain packs 1–2 weeks before the December implementation date.

Conclusions The early indication is that plain packaging is associated with lower smoking appeal, more support for the policy and more urgency to quit among adult smokers.