A euthanasia advocate says enough doctors support assisted dying in New Zealand to treat the number of people who might seek it.

Former president of the End of Life Choice Society Dr Jack Havill says a survey of GPs has found more than a third support terminally ill people having the right to choose to die with medical intervention.

However, 52 per cent oppose it in general, and just 15 per cent say they'd be prepared to actually administer the drug to cause someone's death - if it were legal.

Havill says there's some opposition in medical circles, which he describes as generally conservative.

"They keep saying it's ethically against the medical practice. But I would, and many other people, would disagree with that. We don't think it's ethical to make people suffer at the end of their lives when they are dying already."

Havill says despite minority support, it represents enough doctors to make it work, should the bill pass.

"It's always what's expected. We have 14,000 medical doctors and 30 to 37 per cent in these figures say that there's enough there to make a bill workable."

The results are from a self-selecting survey by NZ Doctor magazine.

LISTEN TO JACK HAVILL TALK WITH MIKE HOSKING ABOVE