Medicinal cannabis can only be prescribed by a registered medical practitioner after a thorough assessment to decide if the treatment is appropriate for your condition and individual circumstances.
If a doctor decides that a medicinal cannabis product is suitable for you, they must apply for approval to prescribe it under the applicable state or territory laws. Rules relating to medicinal cannabis products vary between states and territories and could affect whether or not medicinal cannabis can be prescribed.
Reference: Medical cannabis products: Patient information