National Party leader Judith Collins says she's been made aware of "other instances" after one of her MPs admitted to sending pornographic images to a young woman.
Ms Collins this morning told TVNZ1's Breakfast that MP Andrew Falloon admitted he sent an image to a 19-year-old.
She said he didn't mention to her that he'd left his phone with friends - one of the stories that emerged after he stepped down yesterday.
Yesterday Mr Falloon announced he wouldn't run at the upcoming election. But this morning, Ms Collins said she wanted Mr Falloon to resign immediately.
Breakfast host John Campbell asked Ms Collins, "Are you hearing about other instances along these lines?"
"I have heard this morning from media that there is likely to be other instances and I would like anybody who wants to to come forward directly to me or to my office, but I also believe that this is something very, very serious," Ms Collins said.
Stuff has reported that Mr Falloon sent sexually explicit photos to another young woman.
"I believe that with Andrew Falloon's changing story that I have no confidence in him and he needs to resign from Parliament today for the sake of his family, of the public and ultimately so he can focus on his significant mental health issues," Ms Collins said.