Legalising medical cannabis would give rise overnight to an industry worth up to $150 million, a new study from the University of Sydney has found.

The NSW government will this year commence clinical trials of cannabis-derived medicine for conditions such as chemotherapy-related nausea. The federal government has also passed laws creating a licensing system for future supply of medicinal cannabis.

But a new white paper from the University of Sydney's business school suggests it would have a major secondary effect: the creation of a multi-million dollar industry centring on the cannabis plant.

"It's about much more than just the medical benefits," said Michael Katz, an author of the study and associate lecturer at the school.