CANBERRA - A controversial pro-euthanasia television ad, which was to air tonight, has been banned.

The ad's creator, lobby group Exit International, says the ban is a violation of free speech and they will try with a different version within days.

The ad shows an ill-looking actor sitting on a bed in his pyjamas.

He reflects on the choices he has made throughout his life, then says he did not choose to be terminally ill.

"I didn't choose to starve to death because eating is like swallowing razor blades," he says in the ad, which can be seen online.

"I've made my final choice. I just need the government to listen."

Free TV Australia, which regulates the industry, withdrew its permission for the $30,000 (NZ$38,165) ad to be screened on the grounds that it promotes suicide.

Exit International founder Dr Philip Nitschke said the right to lobby for legislative change - and to free speech - was threatened by such a ban.

"In an open democratic society, it's very important to be able to advocate openly for law reform," he told AAP.

"They've effectively curtailed any open discussion of political change on this important social area."

Dr Nitschke said he would try again with a different version of the TV ad on Monday.

Exit International will also press ahead with plans for a billboard version in Sydney, and will to try to screen the TV ad in New Zealand.

Dr Nitschke said it would have been Exit International's first TV ad. It was to have aired on the Seven Network.

He said the actor was not terminally ill because to use an ill person may have seemed exploitative.

Euthanasia is not legal in Australia. State laws prohibit anyone from assisting or giving advice to another person to commit suicide.

The Northern Territory legalised euthanasia but the Howard government intervened to override it.

The banned ad can be seen at www.exitinternational.net.

- AAP