The first reading of the proposed law to ban conversion therapy has passed.
The tense debate saw Labour's Louisa Wall tell National it was sitting on the "wrong side of history".
Labour, Greens, Te Paati Māori and ACT voted for the bill and National voted against it, saying the bill was "vague".
If passed into law, it could see someone imprisoned for up to three years in jail for performing conversion therapy on someone under 18 and up to five years where it has caused serious harm, irrespective of age.
The bill still needs to go through multiple steps, which involve public submissions and possible changes, before it could become law.
The debating chamber became heated, with calls of 'shame' echoing from the Government side during National's Simon Bridge's speech.
Bridges told the House that under the bill a mother could possibly break the law if they told her 12-year-old to wait until they're older before going on puberty blockers.
"Absolute nonsense," Deputy Prime Minister Grant Roberson said.
Bridges described the bill as "incredibly broad", saying it "lacks common sense, it is an ideological overreach".
"There must be an exemption for parents."
He said the gender identity expression made the issue "complex".
Green's Chlöe Swarbrick accused the Opposition of not reading the bill.
Associate Health Minister Ayesha Verrall called the practice "traumatic and it is totally unjustifiable", describing it as "sick and bizarre".
"And what is unbelievable this practice is called a theory. It causes hurt not healing.
"It is monstrous, it is not therapy, it is hate."
Labour's Louisa Wall said it was an "abhorrent, disgusting relic of historical position that LGBTQI peoples are somehow wrong".
"We deserve protection."
On the concern around parental prosecution, Wall said, "get real, it's not a real conversation".
She accused the Opposition of "trying to create public panic".
"At the heart of this is our children."
Wall said children were "perfect as they are… National are on the wrong side of history".
Māori Party's Rawiri Waititi said today he was "going to be on the right side of history for this debate".
"Takatāpui are whanau. No ifs. No buts."
"Conversion therapy is a direct attack on our whakapapa."
National's Barbara Kuriger said the party wanted conversion therapy "gone", saying they were voting against it today as they were being "cautious".
"Is it too much to ask we sit down at select committee and have an adult conversation?"
She said it might be "a matter of changing a clause in the bill that will satisfy us we will not cause further harm".
Green Party's Elizabeth Kerekere said the proposed law would hold people accountable for their actions.
She hoped those who perform conversion therapy would "beg forgiveness from their God and their community for what they've done".
"We'll get this through."
ACT's Nicole McKee said her party would see the bill through its first reading but said they would pull support after the Select Committee stage should their "major concerns" not be addressed.
"Conversion therapy is attempting to change or suppress someone by shame, emotional manipulation or through trauma," she said.
McKee said ACT was worried about the impact it could have on families "and discussions it may have in the home" and if a family sought religious guidance.
"ACT is concerned the bill in current form doesn’t just step on parents and religion, it actually stomps on it."
National today came under fire from its own youth wing for its decision to vote against the bill, with the Young Nats saying New Zealanders deserved the chance to discuss the legislation "in-depth and hear expert testimony on the topic".
"Conversion therapy does not work, yet it causes irreparable harm to those within our rainbow communities," a tweet from the Young Nats stated.
National committed to supporting the ban in February, with leader Judith Collins saying at the time, "we think that's the right thing to do".
However, upon seeing the proposed law last week, Bridges said National wanted to support this bill "as much as we support the intent but we're concerned for parents and criminalising of good parents".
Last week, the Government announced proposed laws to fulfill its 2020 election promise after pressure had come on Labour to ban conversion therapy.
The proposal makes it a criminal offence "to perform conversion practices on a child or young person aged under 18, or on someone with impaired decision-making capacity".
Someone performing conversion therapy on a person under 18 could receive punishment of up to three years in jail.
A person could get up to five years in prison if they have performed conversion therapy on a person of any age and it has caused serious harm.
It also would allow for civil redress.
To be considered conversion therapy, it must: "Be directed towards someone because of their sexual orientation, gender identity, or gender expression, and performed with the intention of changing or suppressing their sexual orientation, gender identity, or gender expression".
Calls to ban sexual orientation and gender conversion therapy came in 2018 after TVNZ's Sunday investigated therapy offering to "cure" people.
It revealed that conversion therapy in New Zealand was readily available.
Labour MP Marja Lubeck then introduced a Member's bill in 2018, after a 20,000-strong petition led by the Green and Labour youth wings was delivered to Parliament. It was never pulled from the ballot.
Earlier this year, the Green Party, fed up with the time it was taking the Government to ban conversion therapy, launched a petition for priority to be placed on outlawing the practice.
It received more than 157,000 signatures. National also gave its support to banning conversion therapy. Faafoi said at the time the Government was aiming to have it banned by February 2022.