However, the intensity of the disputes is escalating. And the complaints about other parties are not simply about policy. They are about behaviour.
Peters last week described National, in regard to the India free trade agreements, as having acted with “duplicity” for the past six months.
Luxon suggested on RNZ this week that Peters was trying to “sabotage” the India FTA.
Also this week, Immigration Minister Erica Stanford said Peters was referring to the contents of confidential Cabinet papers over which decisions had yet to be made.
He won’t release the papers, but claims they discriminate against India.
She said that what he was doing was not helpful to New Zealand’s relationship with India.
On a different matter, the Act Party is frustrated by New Zealand First’s shifting positions on health and safety reforms being promoted by Act’s Brooke van Velden.
She all but accused New Zealand First of not telling the truth about the level of concerns they had previously raised with her about the bill.
And Act leader David Seymour this week suggested: “They don’t even know why they oppose it”.
But New Zealand First’s Mark Patterson says he has had a “conga line” of experts, including employers, through his office to explain why the bill was flawed and could reduce worker safety.
“If there has ever been a case that we step back and reassess after listening to feedback to the select committee, this is it,” he said.
“The risks of getting this wrong are high.”
National’s criticism of coalition partners is high-level and calculated.
National campaign chair Simeon Brown controversially used the platform of the party’s annual conference to describe Act and New Zealand First as squabbling children, to which offence has been taken by Seymour and Peters.
Of New Zealand First, Brown said outright, “You just can’t trust them”.
It is generally recognised that Luxon has held his tongue for most of the term and put up with criticisms, overt or veiled, from partners, New Zealand First in particular.
But that tactic was dropped earlier this year when it became clear that New Zealand First’s support was growing at National’s expense.
Peters also stepped into normally no-go areas to comment on leadership issues inside National. He criticised Luxon for putting his leadership to the vote in a bid to cauterise internal rumblings.
He referred to it as a “sort of ego trip” on 1News.
But perhaps the biggest fall-out between partners occurred in April after Peters released sensitive emails, as Foreign Minister, under the Official Information Act to Herald political editor Thomas Coughlan – ahead of alerting the PM’s office about their release.
Prime Minister Christopher Luxon accused Foreign Minister Winston Peters of putting politics ahead of the national interest. Photos/ NZME
That prompted a visit by Luxon from the Ninth Floor to Peters’ seventh-floor office for a “please explain”.
The emails were damaging to the PM in that they suggested that Luxon had initially wanted to express support for the United States’ bombing of Iran. Soon after the email release, Peters said there had been a mistake in the process of the release, then he said there hadn’t.
In an unusually strong statement, Luxon said Peters had not only mischaracterised his position on the Middle East conflict, but had “clearly put politics ahead of the national interest”.
And that was also when Willis first characterised Peters as “confused”.
Willis said Peters seemed “very, very confused”.
“What is to say he won’t have a bout of similar confusion in the coalition talks?”
Confusion is a perfect word with which to needle Peters.
On the face of it, it is a relatively mild criticism but in the context of Peters being aged 81, it has a decidedly different meaning.
And in that context, “confusion” is designed to undermine trust in New Zealand First, despite Peters’ assurances that his party would not form a Government with Labour.
The public is mature enough to know that a coalition cannot be expected to be unified in the way a political party should be.
But what initially looked to be a healthy development of MMP has escalated into an ongoing slanging match that strains coalition relationships privately and publicly.
That is likely to be unattractive to the voting public.
In their own self-interest, it has reached a stage at which the coalition parties should sensibly be discussing a truce or at least setting themselves some parameters.