Political leaders are wrestling to salvage public trust in Parliament after the sacking of minister Iain Lees-Galloway, following an extramarital affair, and a new police investigation into former National MP Andrew Falloon over lewd text messages.

It comes amid reports that Lees-Galloway paid for flights and accommodation for his mistress while he was in Paris earlier this year on ministerial business.

NZME has been told of the Paris rendezvous with the woman - a former staffer from one of his departments - but so far there is no evidence that public money was spent on her.

Ministerial Services - part of the Department of Internal Affairs - confirmed the Prime Minister's Office had asked for "data and information" about Lees-Galloway's use of public funds.

"To ensure expenses are within the parameters for the use of public funds, Ministerial Services reviews all expenditure in ministerial offices according to relevant legislation, determinations and policies regarding ministerial expenditure."

Lees-Galloway was in Europe earlier this year, and Paris specifically on January 15-16 for an OECD meeting. He was back in New Zealand by January 27.

In the period from October 1, 2019, to March 31, 2020, Lees-Galloway spent $24,638 on Cabinet-approved international travel, according to the Department of Internal Affairs.

His most recent credit card statement released by Internal Affairs is for June-July 2019, and shows a $2642 charge for accommodation at the Hotel Royal Manotel in Geneva, Switzerland. He was in Geneva for the International Labour Conference, where he spoke and held various top-level meetings.

There is no suggestion his mistress was with him on that occasion.

However, what is known is that the relationship lasted 12 months and has cost Lees-Galloway his political career - he will not contest September's election.

Lees-Galloway, 41, is married with three children. He said he had "acted completely inappropriately in my position and cannot continue as a minister".

Prime Minister Jacinda Ardern said ministers having affairs was not necessarily inappropriate behaviour, and it depended on each individual circumstance.

But Lees-Galloway's position was untenable because he was the Minister for Workplace Relations and Safety, and he had opened himself up to accusations of improperly using his power.

Ardern said yesterday that Parliament had not been meeting the expectation of the public in recent days.

It now fell to MPs on both sides of the political spectrum to "restore people's faith in our system".

"Ultimately, we do need to take responsibility for making Parliament a place that people can have some faith in, and a bit of trust in," she told the Country.

Meanwhile, NZ First leader and deputy prime minister Winston Peters is capping off a dramatic week in New Zealand politics by saying he will save the Tiwai Pt aluminium smelter. He will be in Southland today.

"I am going to expose decades of deceit from central Government and the Crown with respect to Tiwai Point," he told Newstalk ZB.

He says it will not involve government money. "I am down there to talk plain common sense."

There are currently 119 MPs in the New Zealand Parliament - normally it is 120 but Falloon has already quit.

Asked if the election campaign was gearing up to be a grubby one, Collins said no.

"I think we can get rid of the people out of Parliament who have been actually quite revolting in their behaviours."

On Thursday, Collins revealed a fifth woman had now alerted her to inappropriate messages from Falloon.

Yesterday, police also confirmed they had re-opened the investigation into Falloon's actions.

The number of women who say they have received these types of messages from the disgraced MP was now "at least" five, says Collins.

Police had previously investigated a complaint about the sending of the first unsolicited image, but it wasn't found to meet the threshold for prosecution.

Collins called for anyone else who had received inappropriate messages from Falloon to come forward.

"The more women who come forward to the police, the more evidence the police will have."

Falloon resigned as an MP on Tuesday morning, after revelations he had sent sexual images to a teenage university student.

He had indicated that he would stay on until the election but he stood down after pressure from Collins.

"People involved in this type of behaviour, that he's clearly indulged in, are manipulative."

Speaking to media yesterday afternoon, Ardern said her campaign would be focused on policies, not personalities.

She said when she became the leader of the Labour Party three years ago she had pledged Labour would "conduct itself during elections, and during parliamentary terms, with integrity".

"It is up to us to uphold that and it's the only way we will restore people's faith in our system ... and to ensure that we act with integrity.

"We know what the public expects of us, now we've just got to make sure we're doing that and we display that during election periods as well."

On Wednesday, Ardern announced she had sacked Lees-Galloway from Cabinet and stripped him of his ministerial portfolios after he admitted to a year-long extramarital affair with a former staffer.

At Ardern's request, Ministerial Services is now going back over the use of public funds in Lees-Galloway's office to ensure none was used inappropriately.

A spokesperson for Ministerial Services confirmed that review, saying the majority of that data had already been reviewed as part of standard quarterly ministerial expenditure checks.

It is also possible there will be checks to ensure Lees-Galloway did not use his position to secure any roles, or to disadvantage or advantage the woman.

It is understood the woman now lives in the United Kingdom, and is no longer employed by any New Zealand government agency.

Lees-Galloway – who is married with three children – admitted he acted "completely inappropriately".

Ardern was clear yesterday that Lees-Galloway's position was untenable because he was the Minister for Workplace Relations and Safety, and he had opened himself up to accusations of improperly using his power.

The statement about improper use of power prompted Collins to question whether Ardern knew something that was not public.

Ardern confirmed that she had spoken to Lees-Galloway since her press conference on Wednesday.

"Essentially just as a follow-up after the announcements, but not to discuss anything substantial."

She also revealed she did not know the information her office received was about Falloon.

"I was very explicit, I did not want to know who was involved – I just wanted to go directly to the leader of the Opposition and say nothing of it, and leave it there."

She said that is how these things should be handled.

"Don't play them out publicly, give them to the people who can do something about it and act with integrity."