The New Zealand Drug Foundation said the medical cannabis industry in New Zealand will face competition from overseas medical cannabis companies.
But three United Nations drugs treaties prevented the global trade in non-medical cannabis - that which might be used recreationally - should New Zealand laws change on the use of recreational cannabis.
A Thai drug company has told RNZ its low-priced imports may eventually undercut New Zealand's cannabis market, and investors were not being properly warned.
Drug foundation executive director Ross Bell said it was important for people to understand that products used in medicinal cannabis could be imported and exported, meaning New Zealand producers could join the global industry, and equally they could face competition from overseas medical cannabis companies.
"But when it comes to recreational cannabis, including if we legalise it with the referendum, there are three United Nations drugs treaties which don't allow the global trade in non-medical cannabis."
Read more at rnz.co.nz