Former deputy prime minister Sir Michael Cullen says when he reaches the final stages of terminal lung cancer he wants to decide when the time is right.
"It is not about what some rather too lightly dismiss as 'being a burden'. I do not want my only choice being to die in a near-comatose state on morphine, which has been administered knowing it will shorten my life anyway," Cullen said.
"I do not want to lose control of my bodily functions so that my dignity has disappeared with the ebbing of my life.
"When I reach those last stages, if that is the prospect, I want the choice to be able to decide when the time is right to complete the circle of life."
Cullen today - on Daffodil Day - announced he is publicly supporting the End of Life Choice Act and the Yes for Compassion campaign. He is urging New Zealanders to vote "yes" in the upcoming referendum on October 17.
The legislation would give New Zealanders the option of legally requesting help to end their lives - either by a doctor or nurse practitioner administering the drug (euthanasia) or the patient taking the drug themselves (assisted dying).
To be eligible, patients have to be:
• 18 years or older,
• a New Zealand citizen or permanent resident,
• suffer from a terminal illness that is likely to end their life within six months,
• in "an advanced state of irreversible decline in physical capability",
• experiencing unbearable suffering "that cannot be relieved in a manner that they consider tolerable",
• be competent to make an informed decision about dying,
• have the approval of two doctors, each with at least five years' experience. One can be their GP and the other must be independent.
Cullen, 75, was told unexpectedly in March he had stage four small cell lung cancer while doctors were looking for what they thought might be a heart problem. He had no symptoms and no indication of the disease.
The cancer is inoperable and incurable.
"Chemotherapy has knocked it back. But it will return and I will die earlier than I had been expecting, like so many with cancer," he said.
Cullen said the inevitable end was in the not-to-distant future.
While there is "excellent" palliative care in New Zealand, Cullen said he was still concerned about how he will die but if the End of Life Choice Act was passed it would offer dignity to people like himself with incurable lung cancer.
He said the bill provided a safeguard against pressure coming on the dying person from others and its scope was limited.
"It does not force any medical professional against their conscience. It respects the rights of those who find assisted euthanasia morally abhorrent.
"But it offers to people like me the chance of finishing the life I have enjoyed so much in a way consistent with my moral beliefs and my sense of the dignity of human life."
Daffodil Day was about supporting people with cancer and how New Zealand can reduce the incidence of this complex of different diseases which kill so many, Cullen said.
"Many of us with terminal illnesses think about what the last weeks or months may be like. Our health services talk us through this. Our good people in the hospice movement provide excellent end-of-life care for many.
"We are told our pain can be controlled to a tolerable level. This will suit many of us. But for many others, myself included, there is an overriding issue of control and dignity."
During a 30-year political career with the Labour Party, Cullen rose to be Helen Clark's right-hand man in their three terms in government from 1999 to 2008, as minister of finance for nine years and deputy prime minister for six.
He was the architect of the now-lauded retirement savings plan KiwiSaver, which was launched in 2007.
He has held a number of roles in the civil service since retiring from politics in 2009, including as chair of the Tax Working Group and Earthquake Commission, and deputy chair of New Zealand Post.