Tauranga is New Zealand's fastest growing city and the the bigger it gets, the bigger the challenges.

Anne Pankhurst, from the Tauranga Business Chamber, has lived in Tauranga for 38 years. In that time, the city's population has gone from 55,000 to 155,000.

"Housing stock and housing land is critical in this city, and it's really hard to keep up with that," she says.

"But underpinning all of that is the infrastructure, the sewerage, the roads, all that kind of amenity that needs to come along with it."

Pankhurst believes the city's high growth needs to be met by high investment.

"Some of the infrastructure that sits in the city is still at that village level, but you've got the size of a city wrapped around it now."

National's Sam Uffindel, Labour's Jan Tinetti, and ACT's Cameron Luxton are the three top contenders for the seat vacated by Simon Bridges.

And they know they have a big to-do list.

"We keep hearing the same things, you know. People bringing up the cost of living, the need for better roads and infrastructure," Uffindel says.

Luxton says the biggest challenge Tauranga faces is a history of poor planning.

"Tauranga can be a hub for many different industries, but we just have to get our infrastructure right."

Tinetti, meanwhile, says the work is already underway. She says her place at the Cabinet table as a government minister means she can already advocate for Tauranga's needs.

"We're already investing in infrastructure like we've never invested before," she says.

Funding and fixing the city's infrastructure, then, is the clear by-election biggie.

To solve it, Uffindel is singing from the National hymn book: more roads.

"We've committed to building Takitimu Northern Link, stages 1 and 2 all the way to Ōmokoroa. That's a policy position we've already announced. We're going to be looking at other major pieces of infrastructure in Tauranga and we're going to be announcing those up to the general election next year."

Tinetti says the solution needs to be multi-modal, and factor in public transport.

"If we just build a four lane highway, we're just going to see more cars come onto that and populate that, and we will be in exactly the same issue a few years down the track. But what we need to be looking at, and what we are looking at, is having public transport as part of that."

Luxton, meanwhile, highlights ACT's proposal for an independent infrastructure commissioning agency.

He has also suggested a tunnel through the Kaimai Range for trucks going to and from Tauranga's busy port. But he says it's just a suggestion.

"I just threw out the tunnel through the Kaimai like 'look this is the sort of stuff we need to be thinking about.' I'm not promising anything, I'm not saying it's the right solution, it's up to the industry and infrastructure planning to get onto it. But we can't just allow political promises to be the way we fund and plan infrastructure in New Zealand."

Delivering that infrastructure will require the MP to work with local government.

But Tauranga's local government looks a little different to others: its city councillors were all sacked in late 2020.

Former National party MP Anne Tolley believes the city's biggest challenges are also its biggest opportunities. Photo: Giles Dexter/RNZ.

Since February 2021, four government-appointed Commissioners have worked to steady the ship.

The commission is chaired by former National party MP Anne Tolley. She believes the city's biggest challenges are also its biggest opportunities.

"We feel it quite heavily as commissioners that we've really got to deliver. So at the end of it when the city does go back to full democracy, at least people will see that we have made a difference."

The commissioners' tenure has just been extended until July 2024.

Tinetti hopes that stability will fix Tauranga's long term issues.

"One council's put something through, the next council's come in and flip-flopped on that decision. And so there's been no traction on the ground around the infrastructure that this city has needed. So we know we have confidence now."

But other candidates believe the Commission is an impediment to progress.

Uffindel says he wants to bring democracy back.

"When I've been out there talking to people, a lot of ratepayers have said they'd like the opportunity to vote for their own council. We've got year on year rate increases and people want to have a say on that."

Luxton has gone even further. Last month he compared Anne Tolley to Marie Antoinette, after she outlined the commission's infrastructure priorities for by-election candidates.

"The power has gone to her head, and we say off with it," said Luxton's statement.

A month on, he stands by his comments.

"As someone who's aloof, and spending our money without paying attention to how people are feeling about that, I feel comparing her to Marie Antoinette was perfectly reasonable."

Tolley is a former police and corrections minister. She's built a thick skin over the years. But she admits the comments affected her.

"You have to ask, 'really? Is that all that you can rest your campaign on?' Actually, Tauranga is far more important than me, and the development of this city, I would've thought that's where their focus should've been," she says.

Over the final two days of campaigning, the party leaders of Labour, National, and ACT are all likely to visit the electorate.

Anne Pankhurst. Image: Tauranga Business Chamber.

Anne Pankhurst hopes they leave Tauranga with a better understanding of just how much investment the city needs.

"We have suffered from the thought that we're a city of retirement. And it takes quite a bit for Wellington to actually understand that we're no longer that place."

Whoever it is, Saturday's winner already knows Tauranga's high expectations.

-RNZ/Giles Dexter.