By STUART DYE transport reporter

The Auckland Harbour Bridge clip-ons will need to be replaced in less than 20 years, say Transit engineers.

That means a third harbour crossing, which would take at least 16 years to build, is essential to the future of transport between Auckland and the North Shore, says the Government transport-funding body.

It proposes a bridge to the west or a tunnel to the east of the existing bridge.

But the plans have polarised decision-makers, who are at loggerheads over whether to commit to a third crossing and a giant and costly feat of engineering.

Some members of the Auckland Regional Council's land transport committee say the time for talking is over and the plan must be approved.

But others are calling for alternatives to be explored before $3 billion is committed to the project.

North Shore City councillor Gary Holmes said the committee must give the matter its highest priority.

Mr Holmes, a long-time advocate for a third crossing, said the Transit report made it clear that the clock was ticking.

"The fact that the existing bridge clip-ons may need replacing as early as 2020 is a very compelling reason why urgent decisions need to be made now, a preferred option agreed upon and public consultation begun."

The region could no longer rely on one ageing and inadequate route.

"My fear is we have seen all this before and it has come to nothing from the lack of political will to see it through."

The problems of financing and the potential social impact were daunting, but the outlook if no effort was made to get it under way was far more disturbing, he said.

Mr Holmes preferred the tunnel option between the Northern Motorway east of the present bridge and Wynyard Wharf. It would link with cut-and-cover tunnels southbound to Halsey St and northbound to Beaumont St.

A new bridge, 500m west of the present bridge, would connect Northcote Pt and Pt Erin. On the North Shore a viaduct would connect the new bridge to the Northern Motorway, while across the water the bridge would link to a tunnel running under Ponsonby to the Northwestern Motorway at Western Springs.

Regional councillor Greg McKeown said neither option should be chosen until the possibility of increasing capacity on the existing bridge through public transport was fully explored.

Auckland City Mayor John Banks wants another option - from the North Shore to Mechanics Bay - fully investigated. It would link with the proposed eastern highway that he advocates.

Catherine Harland, chairwoman of the regional council's transport committee, said it was important that Transit was allowed to get on with exploring the tunnel and bridge options, but that it needed to be done cautiously.

"We don't want people sitting here in 20 years' time saying 'why didn't they think of this or that'."

Transit will produce another report giving the committee options on what to do next.

But regional manager Wayne McDonald said the sooner things got under way the better.

Councillors needed to make a decision.

Speed of growth

* Before the Auckland Harbour Bridge was built, 500,000 cars crossed Waitemata Harbour each year by ferry.

* The existing bridge was built with four lanes in 1959, at a cost of £7.5 million (including toll gates and approach roads).

* Within a year, 4.9 million cars were using it annually. By 1965, 9.3 million trips were made across each year.

* The clip-ons were added in 1969 at a cost of $7.4 million.

* The clip-ons have a 50-year life and will need replacing by 2020.

* Today the bridge carries 165,000 vehicles every day.

Herald Feature: Getting Auckland moving

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