"Conversion therapy is unproven, widely condemned and does not reflect the values of a modern and compassionate New Zealand."
She said the bill is about supporting young people to be proud of who they are.
"This is about doing what's right. I hope all politicians approach this Bill with an open mind and support the rights of young people to be who they are and live open positive lives."
She said it is a "straightforward legislative fix" to prevent further physical and emotional suffering as a result of conversion therapy.
Asked about banning conversion therapy, National Leader Simon Bridges said he would need to see a case laid out before making a decision.
Conversion therapy is defined by UK-based LGBT charity Stonewall as "any form of treatment or psychotherapy which aims to reduce or stop same-sex attraction or to suppress a person's gender identity."
NZ Association of Psychotherapists and the NZ Association of Counsellors believe conversion therapy is in breach of every ethical requirement for practitioners.