"Many doctors have said to me privately that they've helped people to die … at their request. It's the choice of the doctor [though] … and they have to do it behind the scenes, illegally," he said.
With no choice whether to die or not, critically ill patients had to rely on the graciousness of their doctor.
"If you don't have a law change, you might be playing Lotto with your doctor."
Davison was addressing the Cape Town Press Club in Newlands.
He returned to South Africa in May after serving a five-month detention in New Zealand for helping his cancer-stricken mother end her life.
She had tried going on a hunger strike but when that failed he gave her a lethal dose of morphine.
Davison pleaded guilty to assisted suicide in the Dunedin High Court last year. He was originally charged with attempted murder and was arrested in September 2010.
On Thursday, he said that he was continuing efforts to bring a draft euthanasia Bill before Parliament, and would approach politicians in the next few months.
His organisation DignitySA was petitioning support on its website.
Davison said he had received considerate support from the legal profession.
"The difficulty has been getting the medical fraternity to speak out … mostly because they signed the Hippocratic Oath."
Ethics Institute of South Africa chief executive Professor Willem Landman had drafted a position paper on euthanasia for the organisation.
In it, he said the key question was whether legalising assisted death would be consistent with the Bill of Rights in the Constitution.
He concluded that a South African had constitutional rights consistent with the moral right to a peaceful and dignified death.
There was a need for a comprehensive Bill that would clarify the legal position on not only assisted dying, but also terminal pain management, the withholding and withdrawing of potentially life-sustaining treatment, and living wills. – Sapa