The fast-track process has begun for a multibillion-dollar project that would radically change inner-city Wellington - but critics say it's on the "fast-track to nowhere".

On Friday, the fast-track application for the SH1 Wellington Improvements project - which envisions the construction of the second Mt Victoria and Terrace Tunnels - was officially lodged.

NZTA said it was a "significant milestone" for the project and would allow officials to protect the route.

But while $185 million has been approved for design, consents and early works, funding for major construction of the plans had not been provided, and there was no start date for building to begin.

In a Wellington City Council meeting earlier this month, councillors opposed to the plan labelled it a "ghost road" and a "ghost project", but the minister in charge insisted the government was committed to delivering it.

What's ultimately on the cards?

An additional Mount Victoria tunnel was a National Party campaign promise, with improvements in the area discussed for years.

NZTA has previously said the total costs to design, purchase land and construct the project would cost between $2.9b and $3.8b.

It would significantly change central city roads, including adding a second Mt Victoria and Terrace Tunnel, and the roads around the Basin Reserve would be re-designed so traffic would move in both directions.

Changes would also be made in Te Aro, with three lanes on Vivian Street and Karo Drive, as well as a widening of Ruahine Street and Wellington Road in Kilbirnie en route to the airport.

Approximately 3.2 hectares of Town Belt would be taken for the project, Wellington City Council officials said in a recent agenda, while hundreds of privately-owned and commercial properties will either be purchased by NZTA or will be right next to it.

NZTA has previously said it had identified 176 properties it might need to buy, and another 146 properties where it might need to buy below-ground land, for the construction of the two tunnels.

So far, $33m has been spent on contractors and consultants.

'Ghost road' or 'gift horse'?

Debate reignited over the controversial project in a council meeting earlier this month, as councillors discussed a list of priorities officials would take to the fast-track panel.

Council officials will highlight key concerns with the project, advocating that less Town Belt land is taken, that people still have the ability to walk safely around the Basin Reserve, that there's adequate walking and cycling space through the Mount Victoria Tunnel, and that disruption from building the tunnels and roads is considered.

The Environmental Protection Authority (EPA) said while timelines varied, on average it took 117 working days for a decision to be made on a fast-track application.

The panel will decide whether to approve the project, approve it with conditions, or decline it within a timeframe.

Motukairangi/Eastern Ward councillor Jonny Osborne questioned why the project was going through the fast-track process at all.

"I would note the project has no funding attached or start date. So you really have to ask yourself why are they fast-tracking it? It's fast-tracked to nowhere.

"But anyway, that's for them to decide, we at council must continue this charade."

Osborne is among a number of Green Party-backed councillors who are [https://www.rnz.co.nz/news/politics/580659/green-mps-councillors-launch-campaign-against-second-mt-victoria-tunnel-in-wellington opposed to the project, saying it "utterly ignores" the reality of climate change by increasing the number of cars on the road, including around Hataitai and Kilbirnie.

"I just want to make it clear that we as a council expect that any of the risks that arise from changes to travel patterns that may happen if this ghost project does happen are mitigated ... especially around schools and other community facilities that are frequently used by schools or other at-risk communities," Osborne said.

Pukehīnau/Lambton Ward and fellow Green party councillor Geordie Rogers, who described the project as a "ghost road", backed an amendment Osborne put forward which sought to use the fast-track process as a route towards pedestrianisation of Cuba Street.

He said the project would increase traffic on roads such as Taranaki Street, Ghuznee Street and Abel Smith Street.

The measure ultimately failed, with Wellington Mayor Andrew Little saying it was a "waste of time" to use the fast-track process for a separate debate on pedestrianising Cuba Street.

"Our role as council is to mitigate the worst aspects of that project."

Not all councillors agree on the issue. Independent Pukehīnau Lambton ward councillor Nicola Young has said she wants the project to go ahead, but doubted whether it would happen for years - or even decades.

The late Tony Randle, who had represented the Takapū/Northern Ward, voiced his support for it, saying it would ease long-standing bottlenecks in the city.

This was crucial if the city wanted to grow, he had said.

"I hope this project is not a charade...this is a project the Government has come and offered us, and don't look a gift-horse in the mouth.

"This will make Wellington better because we are struggling with congestion."

Minister insists project will go ahead

In a statement, Transport Minister Chris Bishop said it wasn't true the Mt Victoria Tunnel project was on a "fast-track to nowhere", or was a "ghost road".

"The project is in the major project pipeline and we are committed to delivering it.

"The SH1 Wellington Improvements project will unlock economic growth, improve productivity, and give Wellingtonians a safer, faster and more reliable connection between the region, the CBD, the hospital and the airport."

A spokesperson for the EPA said the panel can approve a project without government funding attached, so long as it meets statutory criteria of having significant regional and national benefits.

The panel will meet with several invited parties, she said, which change depending on the project.

NZTA's project sponsor, Robyn Elston, said the application is now being reviewed by the team at the EPA.

When it has been accepted as complete it would be made public on NZTA's website, Elston said.

"We look forward to working with the FTAA panel and stakeholders to complete the consenting and approval process."