Australians prescribed medicinal cannabis will now have access to the drug within two days, after a meeting of state and territory health ministers in Sydney.

Patients have been waiting months for access to the drug, under current legislation which sees a double-approval process from both state and federal regulators.

On Friday, all state and territories signed up to the national scheme, which allows the approvals process to be streamlined through one national body.

"Faster access, better access … there will be a one-stop shop for accessing medicinal cannabis," Federal Health Minister Greg Hunt said.

"The decision as to whether or not to prescribe is rightly in the hands of medical professionals, but once that decision is made, access will then be provided within what we expect to be a 48-hour period.

"In many cases, as low as 24 hours."

The single approvals process, through the Therapeutic Goods Administration (TGA), started operating in New South Wales last month.

Mr Hunt argued it had been a very successful trial.

"We've already seen, in New South Wales, the time for prescriptions drop dramatically from two months to two days im that system," he said.

"This is an important day for patient access.

"Now time should not be a matter of concern once a doctor has made his or her prescription."