A former Attorney-General says Trevor Mallard's reign as speaker is safe, despite revelations his false "rape" claim cost taxpayers more than $333,000 to resolve.

Mallard issued a issued a personal apology this week to a former staffer he accused of rape.

He issued the statement the same afternoon of the Royal Commission of Inquiry into the Christchurch terror attacks, prompting claims he was trying bury his apology on a busy news day.

It was later revealed the saga had cost taxpayers $333,000 in an ex-gratia payment and legal fees.

National's leader Judith Collins said the party has lost confidence in Mallard.

"This is unacceptable behaviour from the Speaker of the House. This sheer size of this payout illustrates how serious the matter is.

"Because Mr Mallard has not lived up to the high standards of behaviour that he has set for Parliament, we believe he is no longer fit to hold the role of Speaker."

Former Attorney-General and former National Party MP Chris Finlayson told Newstalk ZB Mallard would continue as leader, despite the payout, because Labour holds a majority in the house.

When pressed on whether he had confidence in Mallard's role as speaker, Finlayson said: "It's a bit of a non-issue because he is going to continue as speaker."

Finlayson said any vote of no confidence would be "ritualistic rubbish" that would go nowhere.

However he had "an objection" to MPs being indemnified for defamation suits.

"I think this has all hallmarks of a bit of a mess. If they open their big mouths and they're sued they should pick up the tab themselves.

Chris Finlayson standing outside Parliament. Photo / File

"Very occasionally there will be those who set out through litigation to impose huge financial costs on a Member of Parliament but that's a very exceptional circumstance.

"Generally I don't see why MPs as a class should be immune from the consequences of opening their traps."

Finlayson said he'd had "issues" with Mallard over the years.

"But I think in fairness he's trying to be parliament's man and he's raised standards of question time because a lot of people are far too lax in the questions they asked.

"If they get a bit of a kick in the pants from him that's no bad thing."

In terms of long-term repercussions, Finlayson said the situation would most likely be subsumed by the other political events.

"I'd say it's got a few days' life left in it and then it will fizz. I don't think it will drift on for too long."

In June last year, Mallard said he believed a rapist was working in the parliamentary precinct.

It was the day after the Francis report, which reviewed the parliamentary workplace, was released.

The report found systemic issues of bullying and harassment, poor conduct too often tolerated and normalised, and a perception of low accountability.

Mallard himself commissioned the report after a series of cases of bad behaviour.

Mallard had said that he believed a man was responsible for three serious sexual assaults mentioned in the review, and that he believed the man was still working at Parliament.

His comments sparked a series of turbulent events that led to the parliamentary staffer being stood down.

Mallard then said that a threat to safety had been removed from the premises.

After Mallard made the comments, the man told Newstalk ZB he felt bullied out of the building.

He said at the time he wanted an apology for what he described as the Speaker's "slanderous" comments.

Mallard has now apologised for the "distress and humiliation" he caused the man.

The false 'rape' claim cost taxpayers more than $333,000 to resolve.

The bill included a $158,000 ex-gratia payment to the former staffer to settle the defamation claim - and more than $175,000 was spent on legal fees.

"Trevor Mallard accepts that his understanding of the definition of rape at that time was incorrect and that the alleged conduct did not amount to rape (as that term is defined in the Crimes Act 1961) and that it was incorrect of him to suggest otherwise.

"Trevor Mallard apologises for the distress and humiliation his statements caused to the individual and his family."

The day after the Francis Review into bullying and harassment in Parliament was released Mallard said he believed a man who was responsible for three serious sexual assaults was still working in the building.

His comments - called shocking by some parliamentary workers - sparked a series of turbulent events that led to a historical assault complaint and a parliamentary staffer being stood down.

Mallard then said that a threat to safety had been removed from the premises.

The staffer later brought a case of defamation against Mallard seeking damages of $400,000 and exemplary damages of $50,000.