"That's what leaders do – Miss Ardern calls it a captain's call, I call it a leader's call."
She said during campaigns, the party's campaigning committee sometimes makes decisions about new policy – that's something which has happened here, Collins said.
Speaking to Newstalk ZB on Monday, Collins revealed National would review Auckland Council.
In a subsequent press release, she said the review would be launched within National's first 100 days in Government.
But, according to leaked emails to Mediaworks, National's Auckland Council spokeswoman Denise Lee had no idea the policy was coming.
In the emails, Lee is reported as saying the plan was "highly problematic," "another working group" and it would be a "nightmare".
She added that for Collins to bypass her when it comes to a policy under which she is the spokeswoman showed "incredibly poor form and displays a shockingly bad example of poor culture".
Collins pushed back on this suggestion this morning – "I'm not making up policy on the hoof," she said.
"Leaders do make decisions – that's part of leadership."
She said the Auckland Council issue was something the campaign team has worked on for weeks.
"Campaign teams do make decisions during the campaign – I understand the MP involved, it's her first time campaigning as the MP," she said of Lee.
Collins said she had talked to Lee about the comments.
Last election, Ardern made what she called a "captain's call" to not rule out a capital gains tax during her first term.
That was a call that was ultimately walked back in the subsequent weeks.
This morning, Collins was also asked about the culture within National after an anonymous National MP told Mediaworks that Collins making policy up on the hoof was "creating division".
When asked about these comments, she said: "I'm sure he apologised," implying she knew which of her MPs was anonymously criticising her to media.
When pressed as to who "he" was, Collins said: "I'm sure you know," but wouldn't say who the MP who.
Pressed again, she deflected: "I've already told you that the issue has been dealt with. I have dealt with it; I'm very aware of the situation that some people get under stress in the campaigns – personally, I don't - I love them."