People are moving away from the black market, as medicinal cannabis becomes more widely available

A study published in today's Medical Journal, reveals the products are becoming more psychoactive, with higher THC levels.

The lead author says many GPs aren't confident in prescribing medicinal cannabis themselves.

But Massey University Researcher Chris Wilkins says commercialisation is transitioning people away from illegal options.

He says it means patients are getting regulated and safer products, while shrinking the black market.