Canberrans who rely on medicinal cannabis to treat serious illness or chronic pain are currently forced to break the law to seek relief, and a number, including campaigner Laura Bryant, have spoken publicly of their constant fear of arrest.

Moves to establish legal medicinal cannabis cultivation are continuing federally, with changes to the Narcotics Drugs Act passed in February, and the Therapeutic Goods Administration and Department of Health advancing plans to lower barriers preventing access.

But there is considerable pressure for more to be done locally. Last month, advocacy group The Med Shed was set up to pressure ACT politicians ahead of the October territory election.

Group co-ordinator Matthew Holmes called on Justice Minister and Greens MLA Shane Rattenbury to provide an amnesty for medicinal cannabis users from prosecution.

Mr Rattenbury was already attempting to convince Police Minister Simon Corbell to do just that.

He wrote to Chief Minister Andrew Barr and Mr Corbell in March, seeking that the police minister use his annual directions to ACT Policing – designed to guide the force's priorities for the year – to create an effective amnesty for medicinal cannabis users.

Mr Rattenbury's proposal sought a direction to police that they not charge genuine medicinal cannabis users with drug-related offences.

He proposed users would require certification by a doctor as having a particular illness, and would be listed on a registry and given an ID card.

Conditions could be associated with the amnesty, Mr Rattenbury proposed, including that the person must not supply the drug to others.

But the government, which is broadly supportive of a national medicinal cannabis scheme, rebuffed the Greens proposal, saying the ministerial police directions were not the right way to create such an amnesty, and that it would have little practical effect, because police already knew to focus their efforts on suppliers, not individual users.

Mr Rattenbury said he was disappointed that the government had rebuffed the proposal.

"This is actually about providing peace of mind to people who are in a very vulnerable place," Mr Rattenbury said.

"They are largely law-abiding people who wouldn't dream of entering into the drug scene per se, but they know that cannabis can be used in a medicinal way," he said.

"They're nervous, and this is about giving them confidence."

The ACT government is supportive of allowing medicinal marijuana use in "limited circumstances for particular forms of illness", but wants a national approach, and a national cultivation and manufacture scheme.

Locally, the ACT is considering how it will need to reform laws and develop clinical guidelines to facilitate medicinal cannabis use.

But Mr Corbell said that his formal directions to police were simply not the right way to create an amnesty from prosecution for users.

He said police already had a wide discretion and an existing practice of focusing their efforts on suppliers, not individual users.

"It's outside the scope and purpose of the [ministerial] direction to do that, the direction is to express the minister's expectations or priorities for policing activity," he said.

"In the meantime, police already have significant discretion, and indeed existing ACT policing policy recognises that law enforcement resources should be directed at suppliers and not users."

"It's really nothing more than the police do day-to-day, in terms of exercising their judgment around cannabis possession and use."

A Legislative Assembly committee report recommended the ACT not move forward with its own medicinal cannabis production scheme last year.

Victoria became the first state to legalise marijuana cultivation for the treatment of serious medical conditions including cancer, multiple sclerosis, HIV/AIDS, epilepsy and chronic pain.

Mr Rattenbury had pushed for the ACT to introduce a similar scheme, but that was rejected by the government.