An expert says Auckland Mayor Wayne Brown’s proposed “free” second harbour bridge between Pt Chevalier and the North Shore may end up costing hundreds of millions, if not billions of dollars.

Brown recently unveiled a plan to use a natural existing lava flow at Meola Reef to support a new Waitematā Harbour crossing to Kauri Pt on the North Shore.

A construction expert says the proposed bridge would need to be integrated into the wider motorway system to be effective - and require a “serious readjustment” of Auckland’s existing road network.

Brown told the Herald earlier this month his proposal would cost a fraction of the price of the previously proposed tunnels.

He said it would cost less than 8% of the proposed tunnels, and land sales would cover the expense of the “free” bridge.

Brown described it as an “obvious, much cheaper and better solution” than Labour’s “idiotic cross-harbour tunnel”.

A second crossing over Auckland’s Waitematā Harbour has been proposed as a way to reduce congestion, provide additional options for commuters on both sides of the harbour and address capacity pressures on the ageing Auckland Harbour Bridge.

AUT professor of construction John Tookey says the proposed bridge must integrate into Auckland's wider network - which may prove costly.

AUT professor of construction John Tookey said the bridge could be feasible, but is “utterly dependent” on how it would integrate with the rest of Auckland’s road system.

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Tookey said Brown had given no specifications, and the plan implied a major readjustment of Auckland’s road network would be required to “link it all up”.

He added the cost of a structure to relieve the existing Harbour Bridge could be “potentially in the high hundreds, if not billions, of dollars, given the length of what’s being considered”.

“A trunk route linking Pt Chev and North Shore into a not an ideal location in North Shore. I’m not necessarily sure how much load that’s going to take off the existing bridge.

“If you’re going to put this level of investment in a piece of public infrastructure, then you’re going to want to get a little bit more of a bang for your buck, right?”

Tookey said a plan must be enacted as construction costs rise and maintaining the existing harbour bridge becomes increasingly expensive.

“If you want to make omelettes, you’ve got to crack a few eggs.

“You’re going to have to bite the bullet to a greater or lesser extent.”

Auckland Mayor Wayne Brown says the bridge would cost less than 8% of the proposed tunnels.

Brown claimed the existing bridge did not cause congestion; instead, it was in the roads surrounding the bridge. The mayor said because the new bridge would have entry and exit points in separate areas, it would be the key to reducing congestion.

North Shore councillor Richard Hills did not agree with the plan but was keen to find alternatives to the originally proposed tunnel.

Hills said the bridge would be “impossible to consent” due to the environmental implications of the project, given it would be crossing Meola Reef.

He also said there would have to be extensive consultations with iwi due to the encroachment on historical reserves such as Kauri Point.

The original plan for the new harbour crossing, featuring two, three-lane tunnels, was created under the Labour Government and unveiled in August 2023. They said it would take decades to build and cost $56 billion.

It was continuously rejected by major transport bodies, who had worked to come up with cheaper alternatives.

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