"I have no regrets about what I did to assist my mother to her death, because I did nothing wrong,'' he said.
"I've done my sentence, but I committed no crime.
"In the same set of circumstances, I'd do exactly the same thing again. Although, I'd rather change the law, so nobody else has to go through what I have.
"I'm not bitter. But I think it's very sad that the law finds me a criminal for an act of compassion.''
Davison's partner, Raine, and children, Flynn (3) and Finnian (1), have been awaiting his return to Cape Town since he was sentenced in the High Court at Dunedin on October 27 last year.
"They are the people who have been hurt most by this, because my children have had no father for seven months. It has been a terrible toll on my family back home. For me, every day was just the same.''
Davison founded DignitySA in South Africa, which will launch a national petition to reform euthanasia laws when he arrives home on Sunday.
"I'm going to arrive back to a huge press conference at the Cape Town airport. South Africa has been fascinated by my case and conviction here. In South Africa, it's seen as a global issue.''
Davison will also address a public forum on euthanasia and assisted suicide on Thursday in Dunedin.
Other speakers include Nelson MP Maryan Street, University of Otago Centre for Bioethics professor Grant Gillett and New Zealand Catholic Bioethics Centre director John Kleinsman.