SOUTH Australia's floral emblem - Sturt's Desert Pea - will join marijuana on a banned list of plants under a proposed change to a Federal Government law.

Several species of wattle - the national floral emblem - and many other popular plants such as wisteria and ornamental cacti would also be included on the List of Controlled Plants because they contain traces of naturally occurring drugs, according to a document released by the Attorney-General's Department.

Law experts and the nursery industry say the proposed changes will make it illegal to sell these plants.

The Law Society of SA said while possession of these plants would not be illegal, nurseries selling them would face the same penalties - up to life in jail - as those caught trafficking large quantities of marijuana.

"In reality, what they are doing is those people in nurseries could be prosecuted exactly the same as those trafficking in cannabis," society president Ralph Bonig said.

The proposed changes are detailed in a discussion paper titled Implementation of Model Schedules for Commonwealth Serious Drug Offences, which was released by the Attorney-General's Department.

In a submission to the discussion paper last week, Nursery and Gardening Industry Australia said the proposal would "have huge repercussions on the Australian nursery industry and the wider gardening public".

The CEO of the SA branch of the industry body, Geoffrey Fuller, urged the Government to use "common sense" and review its proposal or jobs could be lost and small businesses could go to the wall.

"The Government has not thought this through - some bureaucrat has made an arbitrary list of plants but a more scientific approach must be taken," he said.

Mr Fuller said the levels of drugs in these plants were sometimes so low that tonnes of plant material would be needed to produce any consumable quantity of the drug.

"It beggars belief that someone would go into a person's garden to steal these plants and turn them into drugs for consumption," he said.

The Government's discussion paper acknowledges the proposals could have "adverse impacts on industry".

The Minister responsible for Drug Strategy, Brendan O'Connor, said "some ingredients used for manufacturing illegal drugs are contained in commonly occurring plants".

"However, the Commonwealth's drug laws target people who are involved in the illicit drug trade and that will continue to be the case."

With the consultation period ending on Friday, the Minister said he will now "consider the views presented and determine appropriate action".

Detective Superintendent Scott Duval, Officer in Charge, SA Drug Investigation Branch, said "there is little evidence of criminality associated with these plants as cannabis is by far the predominant controlled plant sold, supplied and trafficked".