The Green Party says the Goverment’s choice for a second Waitematā harbour crossing won’t solve Auckland’s growing congestion problem and is “bonkers” during a climate crisis.

It comes as National leader Christopher Luxon supports the decision but has no faith Labour can deliver on it.

The Herald on Sunday revealed the Government had agreed to the most ambitious of the proposed harbour crossings: two three-lane tunnels (one in each direction) for cars and trucks in between the central Auckland motorway junction and Akoranga on the North Shore. The tunnels would be 5-6km long, at least twice as long as the Waterview Tunnel. The goal is to start construction by 2029.

A 21km light rail tunnel would stretch from Albany to the Wynyard Quarter, passing through Takapuna and Belmont. It would be a separate project from the two roading tunnels, and be built in stages after at least the first of the road tunnels was completed.

As the tunnels were built, the use of the existing Harbour Bridge would change: two lanes would be turned into dedicated bus lanes to extend the Northern Busway to the CBD, and some clip-on lanes would become cycling and walkways. Waka Kotahi was also looking into building an elevated walkway above the cycle lanes to separate pedestrians.

The remaining four lanes would be for general traffic.

The details of the proposed second Auckland Harbour crossing. Photo / NZME

Steps would also be taken to rebuild SH1 north of the bridge to raise it up and reduce the risk of flooding.

The indicative costings for the full plan total $35 billion to $44.5 billion, but the tunnels would be built in stages to spread it out. The Government had asked Waka Kotahi to look at funding options and said it was open to considering different options.

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Hipkins, speaking in Auckland this morning alongside Transport Minister David Parker and several Auckland MPs, said there was “no question” additional connectivity across the harbour was required.

“The recent wind-related bridge closures of the Harbour Bridge, and the increasing frequency of flooding on the approaches north of the bridge, illustrate the city’s vulnerability to interruptions.

“These new tunnels future-proof the city’s transport network by reducing reliance on the Harbour Bridge while creating fast new options for getting in and out of the city.”

He didn’t rule out using a toll to pay for some of the project, saying the current Harbour Bridge was formerly tolled.

“All options in how we fund this are still on the table,” Hipkins said when asked whether public-private partnerships or further borrowing could be used to fund the project.

Green Party co-leader James Shaw, speaking to journalists at the announcement of their free dental care policy proposal, said the tunnels weren’t the option that would best address congestion.

“At the very least, they should have prioritised the light rail tunnel first, that would alleviate congestion and then would make planning for the roads clearer exactly what the required demand is.”

“Frankly during the climate crisis, it’s a bit bonkers to be building more roads.”

Greens co-leader James Shaw is critical of the Government's choice for a second crossing. Photo / Mark Mitchell

He claimed this Government had a tendency to “acquiesce” to Waka Kotahi by accepting the most “gold-plated, most expensive, massively over-engineered solutions”.

“It’s one of the reasons why the light rail project in Auckland hasn’t gotten off the ground so far is because [Waka Kotahi] can just make them bigger and more expensive and more unworkable plans.”

Green Party transport spokeswoman Julie Anne Genter said the chosen option proved the Government wasn’t serious about the climate or congestion.

“Two new 3-lane urban motorway tunnels in a climate crisis is pouring fuel on the fire of an already overheating planet.

“These road tunnels are carbon-intensive to build, and they would cost tens of billions of dollars that should instead be invested in low carbon transport options like regional rail.

“It is maddening that on the one hand, Labour can say the economic conditions aren’t right for a fair tax system that will benefit millions of people, and on the other announce unbelievably expensive and poorly thought through transport projects.

“The Prime Minister says money doesn’t grow on trees, but apparently it does grow on roads.”

Luxon, speaking from Kumeū, said the tunnel option was the “right way to go”, given the importance of sufficient car and freight movement across the harbour.

“We’ll have a good look at it in government, but I think a tunnel is what our preferred option has been for some time under the previous government and in opposition as well, so we’ll have a good look at it, but clearly it’s one of those projects that we want to progress as well.”

Christopher Luxon supports the Govt's choice for a second crossing, but not the light rail aspect. Photo / NZME

He believed it was unlikely a Labour Government could deliver on the timeframes set out today.

“It’s just not credible, this government has had six years [and] It hasn’t been able to finish a single roading or infrastructure project, so it’s all too little, too late.”

While Hipkins had little detail on how the project would be funded, Luxon was more clear.

“A big part of that will need to be done through accessing private capital funding and financing tools.”

In a press release, National transport spokesman Simeon Brown said the announcement added to Labour’s light rail “fantasy” as the possible route of light rail between the airport and the CBD was still uncertain.

“This is yet another desperate announcement by a Labour Government that has failed to deliver one major new transport project in their entire six years in office.

“Labour promised light rail to Mt Roskill by 2021 but has yet to deliver a single metre of track, even after spending more than $140 million on consultants.”