"This widespread availability makes it harder for people to quit smoking and easier for new smokers to take up the habit," the report said.
Bream Bay College principal Wayne Buckland said he couldn't see how banning cigarettes from dairies close to schools could "practically work".
"Obviously, as a school we're happy the overall trend in New Zealand is for smoking rates to decline in schools."
But, measures like restricting sales at dairies weren't likely to be effective as long as there were people willing to provide minors with tobacco, Mr Buckland said.
"And you're not going to stop the parents who do supply their kids with cigarettes."
Changes to remove cigarettes from view in shops had helped bring rates down, but often it came down to individual retailers and how well they managed their staff.
Underage smoking rates had dropped in Northland over the past few years, and much of that was owed to ongoing advertising campaigns.
"Keep on doing what we're doing, and hopefully in 10 years' time we won't need the discussion at all."
According to the research, despite legally having to be 18 to buy tobacco, a third of minors still get their hands on cigarettes from commercial sources.
The researchers want the Government to introduce a "comprehensive" range of tobacco control measures, including licensing for all tobacco retailers.
Other options include banning some types of shops, like dairies, from selling tobacco and prohibiting tobacco sales in certain zones, such as near schools.