Simon Bridges is defending his role as leader of the National Party after poor polling, saying the party has had its worst week in living memory.
A OneNews Colmar Brunton poll has Labour up 3 percent to 45 percent, with National at 43 percent, down 2 percent.
The poll was taken from Monday to Friday last week as the Jami-Lee Ross saga unfolded.
Mr Bridges polling as preferred prime minister is down to 7 percent.
However, he told Morning Report he has "come through the fire stronger" after the "toughest, worst week for National I can remember for any leader".
Mr Bridges said that, at 43 percent, National is still polling well.
Mr Ross accused Mr Bridges of being a corrupt politician, citing an undisclosed $100,000 donation from a wealthy Chinese businessman in breach of electoral law. Mr Bridges denied the allegations and Mr Ross has failed to provide any strong evidence of the claim.
Mr Ross was also accused of harassing or bullying four women. He said he is considering his legal options in regards to the complaints.
However, Mr Ross has admitted to an affair with a fellow MP and apologised to a woman he admits he behaved inappropriately towards during a local body campaign his wife was running in.
Mr Ross was taken into mental health care on the weekend and has since been released.
It was revealed last night on Checkpoint that the MP he had an affair with had sent him a long, abusive text message which included the words "you deserve to die".
Despite the tumult, Mr Bridges told Morning Report he does not believe the National Party has a culture issue.
An independent investigation will be conducted into the party, but Mr Bridges said the purpose is to make sure people feel safe and confident enough to report issues.
"We're not complacent about this," he said.
Mr Bridges said the priority now is to make sure the women involved have the right support and Mr Ross gets well.
"Several women have been affected. I want to make sure they feel able to confidently come forward with whatever they need to."
Mr Bridges defended his actions of the last week saying he had done "the right things for the right reasons".
"Last week there were some wrong, defamatory remarks about me. As the leader of the opposition, I have to answer those things forthrightly."
Mr Bridges won't say if doctors approved his naming of Mr Ross as the leaker of his expenses, but said he acted consistent with medical advice he had.
He did, however, admit it was a mistake to call Mr Ross' health issues "embarrassing".
Mr Bridges said the last week had seen the worst things any National Party has dealt with "in living memory".
He also backed party president Peter Goodfellow after it was revealed he had arranged a confidentiality agreement between Mr Ross and a women he had allegedly harassed.
Mr Bridges said the issues had been resolved to the complete satisfaction of the people concerned.
He said Mr Goodfellow had done a superb job as party president and had his full backing.
'It's kill or be killed, that sort of mentality'
However, former National Party MP Tau Henare told Morning Report the harassment complaints should have been handled differently at the higher level.
"I just think that the party and particularly the top guys should've handled this absolutely differently and that is poor old Bridges should've been informed right from the start, but also the people who made the complaints - where are their complaints? Who looked after the victims, or so-called victims? Who looks after these guys? They looked after Jami-Lee."
Mr Henare said the political game was tough but there needed to be change.
"It's stressful, it's kill or be killed, that sort of mentality. I know people out there will say things have gotta change, well they may have to change but this is politics, mate," he said.
"Without dissing any of my former colleagues, I think there's a lot of following and not enough questioning at that level.
"It all comes down to how you treat people, at the end of the day you don't need a lot of flash harry people to tell you that the way you do things is wrong."
Green Party co-leader Marama Davidson told Morning Report it was time "clean up our act" in the political sphere, and National's review addressed a part of that.
"What I'm worried about is these inquiries seem to happen after the fact - and that's around the world, Russell McVeagh included.
"What we need obviously is to have a clear message that people will be protected when they take harassment complaints, that the processes and accountability lines are clear, rather than just investigating issues, not only after the fact, but only if they come out in public.
"I don't believe our systems are up to scratch. I don't believe that the whole political system, including in parliament, is staunch enough about protecting any complaints from any gender actually of any sexual harassment."
She said the Greens were pulling together a sexual harassment policy, and there was work being done across the board on those matters.
Auckland University Professor of Politics Jennifer Curtin told Morning Report the review by the National Party into its culture was a step in the right direction.
"But these aren't just about setting up processes inside the parliamentary party ... and it doesn't necessarily apply just to National ... the party organisation if it was doing this properly and really wanted to understand its own culture ... it needs to go beyond parliament."
"What we do want to see is procedures in place so that if somebody wants to make a complaint of harassment and bullying, that they know how to do that without feeling that there are risks associated with their well-being."
She said the review would bring a greater understanding of what was needed to help victims speak up.
"Until we know political parties have in place procedures that enable people to feel safe in coming forward and making complaints, you can't know whether the culture is one that needs investigating or not."
Meanwhile on the poll rankings, Prof Curtin said considering the hectic week National had, Mr Bridges ranked fairly well.
"It was not like Bridges was high in the polls anyway - so people had already been wondering whether or not he had a firm grip on the leadership."
While Mr Henare said he liked Simon Bridges as a person, he was not sure whether he would still be leading the party in the 2020 elections.