Derek Rowbottom, who was interviewed by police on Saturday, said the calls included two from a man and woman who are prepared to confess publicly if he is charged.
Mr Rowbottom, 44, helped his mother, Alice, 80, to die last Wednesday by twice pressing a diamorphine booster on a pump at her bedside. She had been in Manchester General Hospital suffering from liver cancer and was in extreme pain, unable to eat, drink or move without further distress.
Unable to bear her suffering, Mr Rowbottom said that he noticed the button on the pump and decided to administer an overdose "I just pressed it until the syringe was empty. Then I said to one of the nurses: `There's something wrong with this pump,' and they gave her another one and I did the same again."
Since his admission, made after a nurse saw him giving the second morphine dose, he says he has been inundated with calls of support.
"I seem to have opened something of a Pandora's box," he said before being interviewed by police. "I have had literally dozens of calls from people who say they have done the same thing because they simply could not bear to see their loved ones in so much pain.
"There was one man who said he gave his grandfather an overdose of pills in 1968 because he was in a terminal condition and in pain. And there was a young woman who said that she and her three brothers did exactly the same as I did with their mother. She was being treated for cancer at home, but was in agony. They pressed the diamorphine booster and allowed her to die with dignity.
"Both of these people have told me that if I am charged, they will step forward and say to the police: `You had better take me too'. And I don't believe they will be the only ones. I think there are a lot of people out there who feel they did the right thing and don't want to keep quiet about it any more.
"There needs to be a change in the law that allows people who are terminally ill and in terrible pain to die with dignity. It seems as though a lot of people have done this, but haven't had the courage to admit it because of the law as it stands. Now some of them are coming forward and it will be interesting to see what happens to us.
"I don't feel I have done anything wrong. I was beside myself and just wanted my mother to be at rest. I don't care about the consequences. I am just happy that she is now at peace and free from pain."
Mr Rowbottom, whose wife and two grown-up sons support his action, was interviewed by police at Collyhurst police station, outside Manchester, on Saturday and later released.
"I gave them a taped interview and I have got to go back in six weeks to find out the outcome after the coroner's inquest," he said. Greater Manchester police refused to comment on the case.Reuse content