National MP Todd Muller on a 'tough period,' Judith Collins and his return to Parliament

National MP Todd Muller will return to Parliament for the first time in three months, saying it was no secret his relationship with leader Judith Collins had "disintegrated" but he bears her no ill will.

Muller has been away from Parliament since June when he announced he would retire from politics in 2023 just before taking leave to look after his wife Michelle following a major operation.

It was revealed soon after that his decision followed a confrontation with leader Judith Collins after Muller was dobbed in as one of several unnamed MPs which briefed Newsroom for an unflattering article about MP Harete Hipango.

He returns as Collins faces trouble in the polls and increased speculation she could be rolled by Simon Bridges – the man Muller rolled after the last lockdown in 2020.

On the party's 21 per cent result in a recent Taxpayers Union Curia poll, Muller said it showed a lot of hard work was needed and the party needed to articulate "a set of policies, and perspective and tone that resonates with [New Zealanders'] hopes."

Asked if Collins was the leader to do that, Muller said she had "a tough job".

"I don't bear her any ill will, but I think it's pretty clear to everyone that the relationship between her and I has disintegrated. So it serves no purpose me wading in on that issue."

Collins took over as leader after Muller stood down after less than two months in the job last year suffering from panic attacks and severe anxiety.

In June, Muller was pushed to announce his retirement following a late-night caucus meeting at which the Herald was told Muller was threatened with suspension if he did not go quietly.

Muller said he did not intend to seethe on the backbenches until the end of the term or seek revenge.

Bay of Plenty MP Todd Muller. Photo / George Novak

"It was certainly an uncomfortable experience and a disappointing way to conclude a career that I absolutely love.

"But I'm very much a guy that it is what it is. I don't bear any ill will. It's happened. I certainly don't intend to spend the rest of my life seething over what occurred.

"I was very disappointed. But as my late dad used to say, you can put all the disappointments in a backpack and have it weigh you down, or you can put the backpack on the side of the road and keep walking. That's what I'm doing.

And it's in the interests of me, and in the interests of the National Party that I do."

He said he had been a National Party member for 30 years, and would always be one.

He was comfortable about returning to Parliament, although he would not be back in the bosom of the National Party caucus - he had told caucus he would not attend caucus meetings unless there was an issue of concern to his Bay of Plenty electorate.

He hoped his return would not attract much interest, saying there were much bigger issues to contend with.

"Frankly I think most, if not all, of New Zealand are quite rightly going to be focused on what level Auckland is at and how we're going to unwind ourselves from this Covid mess, as opposed to an MP returning."

He said it was still his intention to retire at the next election and he had not yet considered what he would do after politics.

On his mental health, Muller said the period after his retirement announcement had been hard.

"It was a very tough period, and I can't pretend otherwise. But I'm able to talk about it openly and accept the recovery from mental health challenges is not a straight-line trajectory. You have steps forward and steps back. And certainly, that period was a step back."

He had leaned again on his family and friends, and some of his colleagues had been in touch to see how he was coping.

Muller's initial six weeks of leave turned into three months after post-op complications for Michelle, and then the outbreak of Covid-19.

Muller was stripped of all his portfolios and is now on only one select committee: the Petitions Select Committee.