Doctors will be able to prescribe the medicinal use of cannabis without government approval in South Australia from this week.

The SA Government said it was slashing red tape so the drug could be prescribed for periods of up to two months without a state sign-off being required.

Acting Premier Kyam Maher said the change, which applies from Monday, was made after consultation with key parties.

"We heard that it was extra red tape and an extra layer of administration for doctors to have to get state approval every single time, for every single patient prescribed medicinal cannabis," he said.

"If a doctor in consultation with their patient thinks it's the right thing for them, we've decided you don't need that state approval."

Only medicinal cannabis products approved by the Therapeutic Goods Administration will be covered by the change.

Cannabis in same category as morphine

The Federal Government last year legalised the prescription of medicinal cannabis, leaving the finer details up to the states.

The drug is now in the same category as treatments such as morphine.

"[There has been] a lot of consultation with medical professionals, industry representatives and health consumers to come up with what is a good balance between making sure that the drug is approved, and safe," Mr Maher said.

"[It gives] South Australian patients easy access if their medical specialist thinks it's of benefit for them."

Meanwhile, the SA Government is establishing an Office for Industrial Hemp and Medicinal Cannabis as it considers ways to develop both sectors.

Legislation to let farmers supply hemp for industrial uses passed State Parliament this month.

Hemp is used in the production of such things as clothes, cosmetics and building materials.

Industrial hemp is defined as containing less than 1 per cent of the psychoactive drug THC.