RIGHT-TO-DIE campaigner Dr Philip Nitschke has gained permission to import a drug used in voluntary euthanasia.

He will provide the drug Nembutal to a Victor Harbor woman in South Australia who wants to die.

"The drugs will be provided to her with clear instructions," he said. "They are to help her sleep.

"If she breaches those instructions she will be aware there are significant dangers.

"The patient will also have to sign a statutory notification that she is aware of the risks associated with taking more than one tablet a night to help her sleep."

The federal Therapeutic Goods Administration has approved the importation of Nembutal, a brand name for the drug pentobarbital, for use by two Category A patients, one in NSW and the other in SA.

Category A patients are people who are expected to die within a few months.

Dr Nitschke said he had concerns he might have been "set up" by the TGA by being allowed access to the drug.

"They pointed out in their letter to me, which I immediately sent to my lawyers, that action could be taken if there was not good medical practice applied in the use of the drug," he said.

"That means criminal sanctions. They almost seemed to be warning me."

He would not identify the woman or say what she was suffering from. "I have to be careful because she doesn't want to be identified," he said.

He said the patient in NSW, who was being treated by another doctor, was suffering from motor-neurone disease.

Dr Nitschke said there was not much doubt that Nembutal was the best end-of-life drug.

He had used a veterinary version of the drug in the NT before euthanasia became illegal there in 1997. It had also been used by Judy Garland and Marilyn Monroe when they committed suicide.

Pentobarbital, a short-acting barbiturate, was first synthesised in 1928.

It is used in the US state of Oregon for physician-assisted suicide and is also used by the Swiss euthanasia group Dignitas.

In the Netherlands, a pentobarbital elixir is used for physician-assisted suicide. The drug is also approved for use in executions in the US states of Oklahoma, Arizona and Texas.

The SA Parliament is likely to vote this week on a Bill which provides a medical defence for doctors who provide treatment that shortens a patient's life.

There are also two Bills aimed at legalising voluntary euthanasia on the Notice Paper for debate - one from Labor MP Steph Key and the other from independent Dr Bob Such.

Both parties are allowing a conscience vote on all three Bills.

Dr Nitschke first got the idea to try to import the drug from a Customs and Excise briefing notice sent out in March which warned elderly people about trying to smuggle the drug into the country illegally.

He said the briefing sheet had said that instead of trying to access the drug illegally or trying to buy it on the Internet, people should apply to the TGA.

Dr Nitschke said he had already been in touch with the drug's manufacturers in Europe and they should arrive in Australia as a matter of urgency. He said it was only a small package and the freight costs would be small.

"I will write out the prescription for the patient at Victor Harbor and she will get access to those drugs when they arrive," he said.

"It should not be too long. We will provide the tablets to the patient as soon as we can."

The TGA could not be contacted for comment.