The International Lung Cancer Consortium collaborative study suggested there may be an increased risk after heavy cannabis smoking - the equivalent of one joint every two days - for 20 or more years.
Otago University Associate Prof Brian Cox, who worked on the study, said the results were consistent with previous findings that cannabis contained a mixture of toxic products of combustion similar to that of cigarettes.
The study took into account the results of an Otago University study from the mid-2000s, which found cannabis users who smoked one or more joints every day for 10 years were six times more likely to develop lung cancer.
Prof Cox said this finding ''stood out'' and was likely a bit higher than the actual rate.
''The result might have been outside the ordinary due to chance or it could be because cannabis in New Zealand was more harmful.''
What it did show was that more research was needed, particularly because of the high rates of cannabis use in New Zealand.
''New Zealanders when they take up something, they tend to take it up with gusto,'' he said.
He had a simple message for heavy cannabis users.
''If you are taking stuff directly into your lungs ... unfiltered, you can expect some of those things to be harmful.
''We know it causes other respiratory diseases, particularly emphysema.''
