Some MPs in the Bay of Plenty say conversion therapy is "abhorrent" and doesn't have "any place in New Zealand society", but two have voted against a bill that would ban it.
The bill would make it illegal to try to change someone's sexuality or gender identity.
Taupō MP Louise Upston and Tauranga MP Simon Bridges, were among seven National Party MPs to vote against the bill, which passed its second reading on Tuesday.
Bridges told the Bay of Plenty Times that his concern was about the bill's substance, not its subject.
"I think it is really important the New Zealanders have the freedom to be who they want to be and live how they want to live," he said.
"If changes were made at the committee stage of the parliamentary proceedings around parenting, then I would have changed my vote to a yes.
"Most reasonable New Zealand parents would want the ability to sit down and talk things through with their children.
"This isn't about being bigoted. It is about allowing people to have rights, and parents to be parents."
A representative for Upston said she did not intend to publicly comment on the issue.
Rotorua MP Todd McClay, of National, voted for the bill, but still had reservations about it going forward.
"I'm opposed to the practice of conversion, however, I have concerns about the legislation.
"It is much broader than only conversion therapy ... It looks to penalise parents for talking to their children, and criminalise others for having an opinion."
McClay said he would be seeking amendments to the bill to fix these issues, and if they were not added, he would have to "consider how [he will] vote in the final legislation".
"I stand opposed to conversion, I don't believe it is a practice that has any place in New Zealand society.
"It's really important we get the balance right."
Bay of Plenty MP Todd Muller, also of National, said he had had similar concerns, but voted for the bill because he realised it addressed them.
"Looking at the bill and listening to the debate, I felt comforted that there would be normal protections for family conversations which occur in every young person's life.
"I think they've got the balance about right."
He said conversion therapy was "abhorrent".
"That practice should not be available in this country. People should be encouraged and free to find their own sexuality and identity."
Rotorua-based Labour list MP Tamati Coffey said the bill did not criminalise family conversations.
"Parents will always be allowed to have conversations with their children ... There's no way that could ever be taken away.
"If you take your child to an organisation that intends to 'cure' them, then you've got a part to play as well."
He said voting for the bill was a "no-brainer" for him.
"It's amazing that we can use the parliamentary process to make life better for our rainbow communities."
He said the bill was "trying to fix a problem that has existed in the shadows throughout New Zealand, no doubt in little parts of Rotorua as well.
"Our children are perfect just the way they are, and whatever way they identify."
Coffey's Rotorua youth MP, 17-year-old Raukura Kahukiwa, won her role in part with a speech about conversion therapy.
She told the Rotorua Daily Post the bill "essentially protects the impressionable youth within the rainbow community from being subjected to mental, emotional, and physical abuse".
"Suppressing the sexual orientation of someone by 'praying the gay away' is simply ineffective and has been linked to long-term mental health damage and suicidal ideation.
"Despite the great accomplishments regarding this bill, I still believe there is work to be done, in particular with supporting survivors and victims of the practice."
Bay of Plenty-based Labour list MP Angie Warren-Clark said she was proud to vote for the bill and found it upsetting conversion therapy had been allowed for so long.
"We know that these practices do not work, and, in most cases, cause serious and long-term harm.
"I thought about my own family and how I would feel if they were subjected to conversion therapy. I believe that our rainbow community have the right to live free from the discrimination and harm that these practices exemplify."
She said the bill "strikes the right balance" between protecting rainbow communities and protecting individual freedoms.
"It does not outlaw a person's right to hold a belief about sexual orientation or gender identity, and it does not stop parents having conversations with their children who may be wrestling with their sexuality or gender identity.
"It does not limit free speech. Courageous conversation can and should still happen. We don't need to be afraid of this legislation."
Tauranga-based Labour list MP Jan Tinetti said the bill would "uphold the human rights of all New Zealanders, including rainbow New Zealanders, to live free from harm and discrimination".
"This Government committed to ending conversion practices in 2020 and now we are ensuring that promise is delivered on.
"The bill strikes the right balance between outlawing the harm that conversion practices cause and individual rights and freedoms."
The bill now heads to another committee stage where any proposed amendments are debated before its third reading, after which it obtains Royal assent and becomes law.
Waiariki MP Rawiri Waititi was approached for comment.