Dr Philip Nitschke, 61, an Australian, has rejected allegations that he was encouraging vulnerable people to take their lives.

Dr Nitschke's visit came to prominence following an interview he gave to the News Letter on Saturday, sparking immediate protests. Free Presbyterian minister Dr Ian Paisley described the visit as an "abomination".

Dr Nitschke had been scheduled to give a lecture at Queen's in Belfast on Sunday.

But last night a university spokeswoman said: "The Northern Ireland Forum for Ethics in Medicine and Healthcare has withdrawn its invitation to Dr Philip Nitschke to address forum members in a forthcoming debate.

"The reported views of Dr Nitschke were not deemed appropriate for this event."

The controversial medic spoke to the News Letter about how he planned to lecture medical students at Queen's University on his methods which include how to put together and use a suicide kit.

He said he would also talk to the Northern Ireland Ethics Committee about his views and the chilling contents of the kit.

Dr Nitschke who founded right-to-die organisation Exit International, said he was also coming to Britain to take advantage of its "liberal publishing laws" to launch an online version of his handbook.

He said: "I'm giving people all the information they need to die with dignity.

"Christian groups may object to my promotion of self-suicide – but many of the old people who come to see me are Christians.

"Just as some Catholics use contraception, some Christians use my methods.

"Many of these people are in a great deal of pain and want to know how to end their lives without having to implicate anyone else in assisted suicide, which carries a jail penalty."

However, pro-euthanasia campaign group Dignity in Dying branded his advice irresponsible and illegal. Dr Tony Calland, chairman of the British Medical Association's ethics committee, said the doctors' organisation didn't support assisted dying.

"People should have the right to express strongly held views but there will be caveats to that," he said.

"It depends on the vulnerability of people receiving the message."

He said the lobby group recognised that there were tragic cases but maintained there were ways of using palliative care to assist people to die with dignity and the minimum of discomfort.