The forthcoming byelection in Northcote will be a critical early test for the new government and for the new-look opposition. Simon Wilson will be reporting from the electorate right through the campaign.

There's a big hole in the middle of the Northcote electorate, right by the Birkenhead shops. It's a giant slip where a carpark and road just collapsed, disappearing into the mud and slush of the valley far below. How did it happen? What does it mean? How will they fix it? Who could possibly know?

Meanwhile, life goes on. Cars still park in the carpark, right up to where they can't go anymore. There's a building site, with construction continuing all the way to the fence surrounding the hole. It's like everyone's decided to pretend it's not really there.

The hole is just behind the electorate office of Jonathan Coleman, the retiring MP for Northcote. He's not worried about it. In fact, he's not worried about anything. We sat down for a chat in his little cubby in that office and he stretched out, hands behind his head, and said he had no regrets. "Absolutely none."


I was a little surprised, and told him so. What about the scandalous state of the buildings at Middlemore Hospital, several of which have rot and mould and sewage in their walls? Wasn't he the minister of health who presided over that?

"I can tell you right now I had no knowledge of that at all," he said. "Absolutely none. And," he added, speaking each word carefully, "I don't lie."

He said the Counties-Manukau district health board chair Lester Levy told a parliamentary select committee in February this year that they had two problems. "One was increased demand and the other was management of ageing infrastructure." But he said Levy had not gone into any detail.

"It was never raised with us," Coleman said. "Look. If I had known, this would have gone to the top of my list."

Coleman cast himself as the champion of health. He told me that as health minister he battled inside Cabinet and caucus for more resources for his sector. "I asked for more money for health in each budget. It's no secret that I advocated for more spending on health and education, instead of tax cuts."

I asked him how all this plays out in the Northcote electorate. He said he was proud of the health services on the Shore. "North Shore hospital and the Waitemata DHB have a good record." Later, he expanded on that. "The elective surgery centre at the hospital provides top-class service."

It has to be said, Northcote loves a winner. Its MP has been a member of the governing party in every election since 1996 – except 2005, when Jonathan Coleman narrowly won the seat from Labour's Anne Hartley but Labour narrowly held on to power anyway. And 2017, of course, when Coleman held the seat against the overall swing to Labour.

Which makes it a bellwether seat: where Northcote goes, New Zealand goes. But is that still true? We're about to find out.

Also, Northcote loves Jonathan Coleman. The electorate vote for him was close to 60 per cent at its peak and was always several points stronger than the party vote for National itself. Even in 2017, despite that swing to Labour, Coleman himself received almost exactly the same number of votes as he had in 2014.

The Northcote electorate sits to the west of the motorway just past the harbour bridge. Its northern boundary runs in a jagged line from the Tristram Rd motorway interchange to Kaipatiki Rd, and the rest is bound by the coastline. It's packed with suburbs, the big commercial and light industrial areas of Glenfield and lower Wairau Rd, and a lot of bush. Coleman called it the greenest electorate in the city.

He also said Northcote is to central Auckland what Brooklyn is to Manhattan. Well, there's no harm in being fanciful. He meant it's a dormitory suburb in transition, a good place to live close to town. It has, he said, growing wealth, more young couples and families, and more gentrification.

He was talking about the coastal suburbs, especially Beach Haven, Birkenhead and Northcote Point. Northcote itself is not changing in quite that way and, further inland, Glenfield certainly isn't.

Despite the villa-mansions of Northcote Point, the Northcote electorate is not wealthy. It's not like the next-door North Shore electorate, based on Takapuna and Devonport. But nor is it poor, like some of the seats in the south and west. Most of Northcote's schools are mid-decile, not high-decile. It's a mid-level suburban seat.

And that is precisely what makes this byelection so important. The result will not critically alter the makeup of Parliament. But it will send a powerful message to both Labour and National about which one of them New Zealanders are listening to right now. It's the first popular test of Jacinda Ardern's new government and Simon Bridges' new opposition, and it will caution or embolden them both.

By one line of reckoning, seats like Northcote are now safe for National. They enjoyed prosperity under the last government and want to retain it. That's the John Key legacy, if you like.

But the contrary view is that seats like Northcote missed out on much of that prosperity. They're full of people struggling to grasp why they may not be able to buy a house in the city they call home. Certainly, if Labour is to hold onto power at all, it has to be able to convert that sentiment into votes.

The byelection date has not yet been announced, but it's likely to be a Saturday between May 19 and June 9. There's a budget, All Blacks test and Queens Birthday weekend in that period, which suggests the most likely date is May 26.

National has already announced a shortlist of five candidates; both parties will select their candidates next Sunday. None of the other parties have yet announced their intentions.

As for that hole behind Coleman's electorate office, what does it really mean? You can't blame National or Labour, Coleman told me. But is it a stretch to think of it, right in the middle of moderately comfortable Birkenhead, as a metaphor for Middlemore Hospital?

Because one way or another, like it or not, how Northcote voters feel about the health system will have a big bearing on this election.

Simon Wilson's Northcote Notebook will report on the campaigns, the people and the issues of the election. If you'd like to raise an issue with him, email