Collins also said that yelling at your staff isn't usually a sackable offence, but she still supported senior MP Nick Smith's decision to retire from Parliament.
Smith, who will retire next week, has gone on leave and may decide not to return to Parliament before he retires on June 10.
The Herald understands there is no pressure from the National Party for him to return to work next week.
On Monday Smith said he was told on Friday that the details of an employment inquiry had been leaked to media and were about to be made public.
The inquiry was over a verbal altercation - described to the Herald as angry words from both sides - between Smith and a party staffer, who no longer works for the party.
It was recorded by a third party, who worked in a nearby office and then laid a complaint with Parliamentary Services.
Smith has apologised for the outburst.
Asked if yelling at a staffer was a sackable offence, Collins said: "Certainly not."
She said it was Smith's decision to resign from Parliament and she supported that decision.
"I just don't know what's in the [employment inquiry] report," she told The Country.
"Ultimately Nick Smith's got opportunities in life. He's an engineer. He's going into his family's business, and I think he just wants to move on after 30 years of the sort of petty behaviour that we see from time to time, particularly the sort of nonsense of people parking up beside his house.
"Some people need to understand that Nick's done a great job for Nelson and for the National Party."
Asked about Bezzant, she said it was an issue for the party.
"They've dealt with it. He's no longer even a member of the party. He'll never be a candidate for us again."
National has had a number of members resign in disgrace, including Bezzant and MPs Andrew Fallon and Hamish Walker.
"It is really important we sort this stuff out," Collins said.
"Ultimately the selection process that the National Party has dealt with - that's been part of the review that's been done," Collins said.
She would rather not be talking about Bezzant, she said.
"We're getting on with the job, that's why I find it somewhat frustrating to talk about people who've never been elected to Parliament, wanted to be in Parliament but aren't, and never will be."
Collins was in Tauranga today and declined an interview with the Herald, as she did yesterday.
National MP Chris Bishop declined to comment on the damage that the whole episode with Bezzant had done to the party.
"People can make their own mind up about that. I don't think any political party wants candidates to have publicity like he's had in the last 48 hours," he told reporters at Parliament today.
Yesterday Collins wouldn't confirm or deny whether she had told Smith on Friday of an imminent media story into the employment inquiry.
A Politik article claimed that she had, which had intentionally or unintentionally led to Smith's retirement.
Politik also claimed that Collins had warned her caucus early last month that media were "about to break a scandal" involving one of the party's MPs, though she didn't name Smith.
The Herald has been told by other National MPs that Collins' warning did take place.
Collins told RNZ yesterday that she did not disclose what happened in caucus.