Maori could expect a five-year gain, while the life expectancy of non-Maori would be three years longer if sales ended by 2020 and the gains projected to 2040, researchers from Otago University, Wellington, say.
This was compared to life expectancy if smoking rates stayed the same as they were in the 2006 census.
"This is a win-win situation," lead researcher Tony Blakely said.
"Making New Zealand free from tobacco sales not only improves everyone's life expectancy, but it also substantially reduces health inequalities between Maori and non-Maori."
Currently just under 50 percent of Maori smoke, and about 22 percent of the whole population, with 4500-5000 tobacco-related deaths annually.
Professor Blakely said there was growing momentum among the public and politicians that it was time to end the tobacco epidemic.
The Maori Affairs select committee was soon to report to Parliament with recommendations, following its inquiry into the effect of the tobacco industry on Maori.
"Phasing out the sale of tobacco by 2020 would be the single most important and feasible action to reduce Maori mortality and ethnic disparities in this country," said Prof Blakely.
Prof Richard Edwards, co-author and lead researcher on projects looking at how to end tobacco sales in New Zealand, said enough was known now about how to reduce smoking to start a 10-year countdown to zero tobacco sales.
"A 'sinking lid' in tobacco imports, accompanied by massive increases in tobacco cessation activity and other supportive measures to promote quitting amongst smokers and to stop children starting, will see New Zealand effectively tobacco-free by 2020," he said.
A companion paper in the journal presents trends in survival and lifetables, necessary for projections of life expectancy to 2040.
Dr Kristie Carter, lead author of the paper, reported that the differences in life expectancy between current smokers and people who never smoked was about seven years during 1996-99 -- the most recent period with the necessary data.
If nothing was done, and smoking persisted at current rates it would become an even greater constraint on life expectancy and reduction of health inequalities in future, Prof Blakely said.
The research arose from the New Zealand Census-Mortality Study, funded by the Health Research Council and the Ministry of Health.
