Prime Minister Jacinda Ardern said she wasn't interested in playing dirty politics when it came to handling information about National MP Andrew Falloon's improper text to a teen.
This morning, Mr Falloon resigned from politics - effective immediately - after it emerged yesterday that he sent a pornographic image to a 19-year-old woman.
National leader Judith Collins this morning told TVNZ1's Breakfast she was told about the incident, involving an image of a woman, on Friday.
She also said she has been made aware of "other instances" reported in the media.
Later on Breakfast, Ms Ardern said her party received correspondence from the complainant Wednesday, that it was "tightly managed" to respect the confidentiality and privacy of the person who wrote in, then she was given a general briefing herself on Friday morning.
She said she didn't know what the image contained.
"My immediate response was - and I was given general details, not the name of the MP and certainly not the name of the complainant - my view was that ultimately it needed to be dealt with by the person who had the ability to deal with it and that would essentially be the leader of that MP's political party."
Ms Ardern sought permission from the complainant, then the correspondence was passed on to Ms Collins on Friday.
If it was one of her own party members, though, Ms Ardern said she would sit down with them to talk about it but that they would "no longer be a member of Parliament".
"When I took over as leader of the Labour Party I was very deliberate in saying that no matter what else was happening in politics, that I was absolutely determined that we within our team would try and change the culture of politics, that we would campaign positively, that we wouldn't involve ourselves in personal politicking or in what people often call dirty politics," she said.
"In my mind, that if we wanted to restore faith in political institutions, if we wanted a strong democracy, we need people to look to this place and to the politicians and parties within it and have a bit of faith in us.
"So we can do our bit, each as political leaders to try and change those cultures, and so I will take responsibility for that with my team and, as much as I can, for trying to set a tone but we all have a role to play in that."