A Victorian government plan to make clinical trials of medicinal marijuana easier to conduct will do little to expand access to the drug, an expert on drug law reform says.

In response to growing calls for cannabis to be legalised for people with certain illnesses, including children with intractable epilepsy, Victorian Health Minister David Davis said on Thursday that he would amend the Drugs, Poisons and Controlled Substances Act to make it easier for doctors to conduct clinical trials of medicinal cannabis.

Victorian Health Minister David Davis. Credit:Justin McManus

He would also consider removing a prohibition on the "cultivation of narcotic plants for therapeutic purposes in the context of approved clinical trials" and gave "in principle" support for Victorians to be part of an international trial of Epidiolex - a cannabis-based pharmaceutical being tested overseas in children with epilepsy. However, it is unclear when such a trial could begin.

While the Victorian branch of the Australian Medical Association welcomed the government's approach, some doctors questioned what, if anything, would change given a cannabis pharmaceutical - Sativex - is already being used in clinical trials in Australia. Cancer patients at the Royal Melbourne Hospital have been receiving it in a clinical trial since 2012 to see if it eases difficult-to-treat pain.