From yesterday, brand imagery will be replaced by standardised brand names, and large pictorial warnings, set against a muddy-green background.
Aspire2025 co-director Janet Hoek, of the Otago marketing department, said the plain packaging policy was a major step forward in protecting young people from smoking initiation.
But she also urged the Government to ensure standardised packets maintained their impact on smokers.
Prof Hoek and her team had been concerned by evidence from their earlier work which revealed young people rationalised warnings about long-term harms caused by smoking. Accordingly, the researchers had developed and tested a range of new warnings.
In two Health Research Council-funded studies, recently published in Tobacco Control and the Journal of Health Communication, the researchers examined how young adults responded to different warning themes.
Emeritus Prof Phil Gendall, lead author of both studies, said researchers found warnings illustrating the ''social risks of smoking and the harm smoking inflicts on innocent third parties, such as children and animals, as well as exposing the tobacco industry's practices, elicited strong negative emotions''.
Prof Hoek yesterday emphasised the importance of developing anti-tobacco images and messages that were effective for young people, and of refreshing the overall anti-smoking images.
''We must recognise that people who have smoked for 30 years differ from young people who are experimenting or who regard themselves as social smokers,'' she said.
Pictorial warnings had been used for 10 years, she said.
On-packet warnings needed to resonate with diverse groups of smokers, and be refreshed regularly so smokers were exposed to ''multiple reasons for quitting''.
With only seven years to reach the Smokefree 2025 goal, there was a need to ensure that the policies introduced ''achieve maximum impact over a sustained period'', she said.
