The government has announced that it will establish a medical cannabis scheme as a "priority" and "as soon as practicable".

Assistant health minister Meegan Fitzharris said setting up the schemeit needed to be done in a way that was evidence-based and supported vulnerable people.

"The ACT's scheme will work to establish the ACT as a leader in the research and development of cannabis products here in Australia and develop a framework for the prescription, use and distribution of medicinal cannabis to those who need them on medical grounds," she said.

The move has been hailed as long overdue and a "significant" breakthrough by medical cannabis advocates and supporters.

ACT Greens member Shane Rattenbury welcomed the announcement, having pushed for a medicinal cannabis scheme in Canberra for over two years, but warned it needed to be "acted upon genuinely and swiftly".

"In the past there have unfortunately been policy commitments on medicinal cannabis by other state governments which have never come to fruition – for example over a decade ago NSW promised a medicinal cannabis scheme when under public pressure only to later abandon the promise and make no progress at all," he said.

Canberra medical marijuana campaigner Mark Heinrich, whose home was raided by police in 2014 after he provided cannabis oil to a two-year-old girl, said the ACT scheme would be life saving and life changing for many people.

"It is long overdue and a step in the right direction. I just wish that it had happened a lot sooner," he said.

"It's not just life changing, it's life saving, particularly for young babies with epilepsy that isn't controlled by conventional medicines.

"The patients will be the beneficiaries of this in the long run. They just have to work out how to get the supply issue sorted out and that's something that is going to take a bold step by the government to actually make it happen."

It is unlikely the ACT would be able to support medicinal cannabis production, Ms Fitzharris said.

The move comes after the Therapeutic Good Administration recently decided to reschedule cannabis from a prohibited substance to a controlled drug.

Ms Fitzharris said this allowed the ACT to treat medicinal cannabis in the same way it treated other medicines.

"At the moment, there are no clinical guidelines on what types of conditions medicinal cannabis can and should be prescribed for," she said.

"The ACT government will develop evidence-based guidelines to inform and support medical practitioners in how to best prescribe medicinal cannabis products. We will also develop education materials for clinicians and the general public to support these guidelines."

Mr Rattenbury wants the scheme to be in place within a year, with an amnesty in the interim "for genuinely ill people in possession of small amounts of cannabis for medical use".

He wanted the scheme not to be too restrictive and called on the government to open it to people with terminal illnesses as well as other serious illnesses, including children with severe epilepsy, with a doctor's involvement.

He also called for the scheme to not be limited to pharmaceutical cannabis products, "of which there are few and which are likely to take many years to develop further".

Mr Heinrich hoped the ACT scheme would enable him to return to being able to provide medicinal cannabis products to patients.

"There's not a lot of good information out there and there are a lot of charlatans and predators and if the government does a licensing system for supply, it'll take it out of the hands of these people who are making money out of other people's misery," he said.

The ACT expects the scheme to be in place by next year, with the territory following in the footsteps of Victoria, NSW and Queensland.

The announcement comes six weeks after the University of Canberra began a $1 million collaboration with Cann Pharmaceutical for a cannabis therapy trial for the treatment of melanoma.