Legislation banning gay conversion therapy, a practice described as monstrous and traumatising, is making its way through Parliament but not everyone is on board.

"I was sent to a counsellor who told me that I could change my sexuality ... if you have people who are telling you that you need to change something which is actually fundamental to who you are, it does do lasting damage."

Paul Stevens has first-hand experience of so-called conversion "therapy" - the harmful practice of trying to change someone's sexuality - first hand, but moves to ban it so far have seen confusion and division envelop both Labour and National.

Justice Minister Kris Faafoi introduced the Conversion Practices Prohibition Legislation Bill last Friday.

Justice Minister Kris Faafoi

The bill creates a pathway for civil redress, as well as two new criminal offences:

Up to three years in prison for performing conversion practices on people under 18 years old or with impaired decision-making capacity

Up to five years for conducting conversion practices that cause serious harm

In an interview just hours later however Faafoi struggled to explain it, and did not rule out parents being criminalised for preventing their children from taking hormone blockers.

It was a communications blunder that recalled his disastrous approach to hate speech legislation, and has commentators questioning whether he's just had enough.

Faafoi himself believes he has been clear enough in selling the bill's intention.

"I think we've made it clear what the intent of the bill , it's to make sure we're preventing harm."

The bill is no godsend for National either.

Read more:

Former victim of gay conversion therapy lauds government's move to ban it

Conversion therapy ban legislation passes first reading at Parliament

Young Nats break with party over conversion therapy vote

The trip wires in legislation banning conversion therapy

ACT, National warn of conversion therapy bill 'risk'

Leader Judith Collins signalled in April the party supported a ban, but ahead of its first reading on Thursday justice spokesperson Simon Bridges said the party would not back it without changes, a move that prompted outcry from the party's youth wing.

Political commentator and National Party member Liam Hehir says social issues will always be a sore spot for the party because of its very nature.

"The National Party ... it's a conservative party and a liberal party so there's not going to be a high degree of consensus ... that's just an outcome of being a big-tent party of a broad-church party." …

Go to this episode on rnz.co.nz for more details