National MP Maggie Barry hopes she has the support to vote down the End of Life Choice Bill tonight.
David Seymour's assisted dying bill is scheduled for its second reading debate at 7.30pm, with a vote expected around 10pm.
As currently drafted, the bill would allow New Zealanders to request assisted dying if they have a terminal illness or suffer from "a grievous and irremediable medical condition".
The bill passed its first reading by a massive 76-44 margin in December 2017, but MPs opposing the bill predict a dramatically tighter margin of less than five votes on the second reading.
On Newstalk ZB this morning Barry told host Kate Hawkesby that there are still a few MPs who haven't made up their minds.
She said the vote was really close, "probably too close to call at the moment".
"But we have come a long way from 76 in favour of the bill and 44 against. The gap has narrowed."
Barry, a MP for the North Shore, fundamentally opposes the bill and has proposed 120 amendments – that means a third reading once all the amendments are looked at will likely be a year away.
She said that many of them cover cultural considerations for the likes of Māori, Pasifika and Muslims.
"The Muslim community came out yesterday and said they were completely against the euthanasia assisted suicide bill and are asking the people to stop it.
"So we will take into account their cultural considerations and put together supplementary order papers – each one of which can take many hours to debate."
Another consideration was the medicalisation of euthanasia and whether doctors and health professionals are comfortable being involved.
"Removing doctors and health professionals from the process of injecting people with lethal toxins, that is certainly going to be a very concentrated part of our supplementary order papers," she said.
Barry said there were a phenomenal amount of loop holes with the bill, and no protections for the vulnerable.
She said that if the bill was to pass and assisted suicide and euthanasia was legal, a slippery slope around the criteria would begin.
"Less than five per cent of the world's jurisdictions have gone down the euthanasia track and changed their laws.
"The vast majority won't have a bar of it and I am quietly hopeful New Zealand won't either.
"We have wasted thousands of hours on it, it's not fit for purpose and it's not fit to be a law.
"It is a dreadful bill and there are those of us in parliament that know it really well, and we will do whatever we can to stop it progressing because it will have a terrible affect on the deaths of our most vulnerable people.
"There aren't safe guards and that is what worries me."
Earlier this week 1000 doctors signed a letter saying they "want no part in assisted suicide".
They urged politicians and policy-makers to let them focus on saving lives and care for the dying, rather than taking lives, which they deemed unethical - whether legal or not.
The doctors said they were "committed to the concept of death with dignity and comfort", including effective pain relief and excellence in palliative care. And they uphold the right of patients to decline treatment.
But the 1000-strong group said it believed "physician assisted suicide and euthanasia are unethical, even if they were made legal".
However, Prime Minister Jacinda Ardern said yesterday she'll be backing a the bill legalising assisted dying in order to let individuals make their own choices.
"It's been my view that while there are a range of strongly held beliefs, and people have the right to hold those, I ultimately want people to make their own individual decisions," she told reporters.
"The best way I can do that is by enabling them to have that choice and by voting in favour."
'I hold grave concerns for my community'
A woman whose condition would qualify her for euthanasia has grave concerns about the End of Life Choice Bill.
Kylee Black is a member of Defend NZ and has an incurable and life-threatening connective tissue disorder, which would qualify her for euthanasia under the current bill.
She said those who are eligible should be asked what they think about the bill.
"We have been given very little opportunity to sit down and really talk with those who are pro-euthanasia about our concerns, and why we are so concerned with this bill," she said.
"I understand where the conversation is coming from and why people are asking for it, but as someone who is eligible for the bill, as a young person, I hold grave concerns for my community."
Black said if the euthanasia bill goes through, for the rest of her life she will have to make an active decision to not choose death.
"And how do I do that? I go through dark times, I have been suicidal, and it's not just bad days, it can be bad months.
"I've had six surgeries in the past year I need my community to wrap around and support me.
"I don't know how I will not make the choice. I can't trust myself to not make a choice for euthanasia," she said.
Black said before she will support a bill, she wants to see active engagement with those eligible on what they think and want.
"Because our concerns haven't been heard. We have tried to connect with many people and we can't - and in the end it is our lives on the line.
"They talk about it as choice, and us all having the ability to choose, but it's not a choice if I don't have a choice over the support I get, over the equipment I have access to and my ability to participate in the community, and the medications I have access to that gives me quality of life.
"If the only choice I have is euthanasia, then that isn't a choice because it becomes a solution."