What a stunning result in the Colmar Brunton poll. Stunning.

Support for Labour has soared to 37% - its highest level in a decade, and Jacinda Ardern is neck in neck with Bill English as preferred prime minister. Both sit on 30%. The country's split.

National will be nervous.

Labour will be buoyed by this.

And suddenly we have to stop referring to Winston Peters as the king-maker. He may well be a queen-maker instead.

The collapse of the Greens has helped Labour. Of that, you can be sure.

To drop 11% in a poll is devastating. One moment of madness, one ill-thought through stunt designed to shore-up the Greens' social policy, and suddenly they're gone. The Greens are in an echo chamber now. No-one's listening. And they're limping their way towards September 23rd and the prospect of political oblivion.

National is on 44%. And that's a good place for the party to be, but they can't form a government with their usual support partners. Like Labour, National will need Winston Peters. Peters is no fan of either party - but he despises the Greens more. And so the prospect of forming a coalition with Labour - and just Labour - will be a lot more appealing to Peters and the New Zealand First party faithful.

But the rise of Ardern and the so-called 'Jacinda effect' is what is truly stunning about this poll.

Sir John Key, perhaps not very helpfully for the Nats, pointed out that Labour did the right thing in making Ardern the leader.

Key said she communicates well. The camera likes her. And people vote for people they like. And they do.

And if you look at the great leaders of the past, they're all great communicators. Never underestimate the appeal of a good orator and someone who can speak to the public with confidence and authority and conviction. Ardern, at the moment, is riding a wave of confidence. She hasn't put a foot wrong.

She handled the situation with Julie Bishop very well. When the Australian foreign minister came out swinging, Ardern gently but convincingly fended off her criticisms. Essentially Ardern's message to Bishop was that it was an unfortunate and inappropriate situation, but that both of them should crack on with focusing on their own political issues.

To that end, there are shades of Helen Clark in Ardern - although Ardern's a warmer, more human version of Clark. But she has Clark's confidence and has her predecessor's ability to unify the party. That became clear as we stood back and watched in essence what was a seamless leadership transition.

Ardern's achilles heel is that she's never been in government and she lacks experience across many important portfolios - the likes of finance and economic development. And that could be her downfall.

But she is smart and she is confident and as the polls show she has wide appeal. Which ever way you vote in this election, it is clearly game on.