Analysis: Christopher Luxon's leadership is hanging by a thread as he arrives in Wellington ready to face his opponents in caucus on Wednesday morning.

In April he stared down his agitators and called a vote of confidence in himself to prove he still had a mandate as National Party leader.

He succeeded in that vote but at the same time put an extraordinary amount of pressure on himself to personally perform better and lift his polling.

There was no chance the caucus leaking and destabilisation would stop unless that happened, and on both measures Luxon has fallen short.

On the latter, the party's polling remains woefully low - last month National was down 2.1 points in the RNZ-Reid Research poll to 28.7 percent.

It was the party's fourth consecutive decline in the Reid Research series and its weakest result since Luxon became leader in November 2021.

On the former, Luxon's personal performance has had moments of reprieve from gaffes and the occasional show of strength but that was all undone last week - a week now dubbed his worst in his prime ministership.

From apologies to business leaders and defending using an NZDF plane to fly him home after a National Party fundraiser, to an 11-year unemployment high, a call to hold a referendum on MMP blindsiding his colleagues in the process, and then a political attack on Labour that derailed into three new National taxes, Luxon went from one disaster to the next.

When Luxon fronted media in April having secured a win in that confidence vote he single-handedly blamed "speculation and rumour" and a "media soap opera" for the position he'd found himself in.

There was no self-reflection that perhaps he hadn't done enough to keep his caucus happy, listened to their concerns, taken onboard their advice, or been willing to change to try lift the party's chances ahead of the November election.

Instead he sent a message direct to the destabilisation faction of the caucus that they were to blame and he had beaten them.

When the rumoured result of that confidence vote started circling in the past week it was clear the anti-Luxon faction were saddling the horses and getting ready to go.

It's now been widely reported that vote was 27-22 and when it was put to Luxon on Saturday he didn't deny it, instead saying he had the support of his caucus.

In theory Luxon doesn't know the result, only party president Sylvia Wood and junior whip Suze Redmayne who did the count know the number, but it's possible MPs dissatisfied with Luxon have been calling around their colleagues and firming up a rough idea of where the vote landed at the time.

If it's true then it would only take three MPs flipping their vote for Luxon to be goneburger.

In the past two weeks Luxon has made two captain calls without first consulting his caucus.

The first was ruling out any arrangement with Opportunity after the election if National is in a position to govern, and the second on Thursday was a commitment to hold a referendum on the MMP voting system.

Captain's calls aren't uncommon but they are usually done from a position of strength and power by a leader who enjoys wide support from their caucus.

Both Sir John Key and Dame Jacinda Ardern made them and did so successfully. Luxon is not Key or Ardern.

If Luxon can't keep his caucus on side - something he'll already know the answer to by the time he heads into that do-or-die meeting - he'll either have to step aside to make way for a new leader or be pushed by his colleagues.

Luxon and any supporters he still has will be hitting the phones late into the evening getting an indication of whether he still has a majority backing him, and if he can win a vote if he calls one.

But that's only half of the issue.

A confidence vote was won four months ago and the prime minister was adamant it had put the matter to bed and here he is again reliving the worst 24 hours of his political career to date.

Winning a confidence vote and trying to keep his caucus in line between now and November 7 could prove more difficult than facing the reality he's no longer the man for the job.

There are just six weeks until the House rises and the official six-week campaign kicks off, and at this point the National Party billboards could be emblazoned with the face of Luxon, Nicola Willis, Erica Stanford, Chris Bishop, or some other outside chance from the front bench.

When Luxon posted on social media that he had called his caucus to Wellington he said it was his "firm belief that division and disunity are a major distraction only 90 days out from the election".

The question many in the caucus will be asking is whether Luxon has contributed to that division and disunity and whether anyone else in the caucus has a hope in hell of mending it in time.

(This story was first published on rnz.co.nz)