National's youth wing is "deeply disappointed" the party is intending to vote against proposed legislation that would ban conversion therapy.
The bill will have its first reading in Parliament today, still needing to go through multiple steps to pass into law.
The Young Nats have been vocally supportive of banning the practice, which attempts to make a person change their sexual orientation or gender identity.
National's justice spokesperson Simon Bridges previously said the party would have supported the bill, but would need to see changes as its current state "leaves parents exposed".
Today, he 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".
"Parents should be allowed to be parents, and be able to say to a 12-year-old, 'we don't think you should go on puberty blockers at this time, we just want to tie-ho and wait until you're a bit older'.
"It's good to have a party that debates these things but the caucus has come to a very clear view."
Young Nats today tweeted that it was calling on National to support the first reading of the Conversion Practices Prohibition Legislation Bill.
"We are deeply disappointed that the National Caucus has decided to vote against the legislation, and believe they should commit to supporting it through the first reading and follow through by proposing workable amendments to the concerns raised.
"New Zealanders deserve 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. The Conversion Practices Prohibition Bill seeks to address this harm and is worthy of further consideration and debate before the House," the statement read.
Changes to proposed laws are possible during stages of the Parliamentary process.
Last week, the Government announced proposed laws to fufill its 2020 election promise, after pressure had been on Labour to ban conversion therapy.
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.