But once the principle of euthanasia has been accepted, how long will it be so restricted?
Those who feel strongly they should have a right to die with medical assistance at a time of their choice will feel the bill does not go nearly far enough. Public opinion is probably on their side.
Polls consistently find a hefty majority in favour of assisted dying, though that phrase, preferred by advocates, might suggest no more than palliative care to many.
Doctors specialising in palliative care oppose euthanasia for the most part. They argue it is unnecessary as well as anathema to their profession. They have told MPs there is no reason for anyone to die in unbearable pain these days.
They concede painkilling doses of drugs can bring on death but believe the important difference is that this is not their intention. Yet if the result is the same, does the intention matter?
These are just a few of the questions most MPs — not all — have been grappling with.
National and Labour MPs have been given a free vote on the bill at all stages. Green MPs made a party decision that all of them would support it. NZ First would not support the bill unless it was to put to a referendum, which begs the question, what are they doing in Parliament?
They are put there, and well paid, to give their time and effort to sometimes difficult issues. At the very least, we should expect them to contribute their considered judgment to the debate, not take refuge in a referendum.
Speaking in Wednesday's committee stage debate, NZ First's Jenny Marcroft said. "This issue basically directly affects the fabric of society and so we believe that temporarily empowered politicians ... alone should not decide on the bill."
That sounds like someone who has thought deeply about the subject, probably more deeply than many of the voters who are now likely to make the decision.
But having got the referendum into the bill, the nine NZ First MPs are probably obliged to vote for it at the final reading. That was the only reason some supporters of the bill voted for the referendum clause.
They, no less than opponents of euthanasia, believed this was a subject Parliament should decide.
They were right.