The Disability Rights Commissioner is calling for the euthanasia bill to be dumped, as the controversial legislation is debated in Parliament again tonight.
Paula Tesoriero says the End of Life Choice Bill is clumsy, and if New Zealanders want it then it should be started all over again.
"This process which is clumsy, awkward, cumbersome and complex continues to pose a number of risks," Ms Tesoriero said.
"If New Zealanders really want this kind of scheme, then start again."
ACT party leader David Seymour, who introduced the private member's bill, has responded, saying, " I mean really I think that the Disability Commissioner is being disingenuous."
MPs are now thrashing out the practicalities, from a person's first meeting with a doctor through to ending their life, one of the major concerns being "coercion".
"Only one doctor has to assess coercion. Courts around the world have grappled with determining whether or not a person is being coerced and yet we're placing this responsibility in the hands of one doctor," Ms Tesoriero said.
Mr Seymour says that's wrong, the bill stating a doctor must ensure "the person expresses their is wish free from pressure" by "conferring with other health practitioners".
Asked does he think it's explicit enough, Mr Seymour said: "Yeah, I think it is because what you've got to remember is if two doctors get this wrong they could potentially go to jail."
But opponents say there's a problem with the words which state a doctor should "do their best".
"You could argue about the wording, you could say they absolutely must. But actually nobody can do better than the best they're capable of," Mr Seymour said.
National MP Chris Penk said: "There's lots of stronger wording and lots of other acts of Parliament, so there's no reason we can't be more robust."
Coercion from family members is the biggest worry.
"Making sure that doctors talk to people who can't benefit from the will, who are not necessarily family members," Ms Tesoriero said..
Mr Seymour's bill has been tweaked to add a six-month window cooling off period where the option of euthanasia remains open once it's been granted.
"Sometimes just having the power takes the pressure off people and they decide that actually they want to die naturally. It's so personal and the important thing here is choice," Mr Seymour said.
In the coming months MPs will debate more of Mr Seymour's changes.
There also remains the question of a referendum and whether the public will have its say.