Peter de Graaf

Northland leaders are welcoming government plans to speed up the construction of an expressway from Warkworth to Whangārei by combining three separate roading plans into one mega-project to be built as a public-private partnership.

The announcement was made this afternoon by Transport Minister Simeon Brown, just days after State Highway One over Northland's Brynderwyn Hills was once again closed by slips.

The latest closure lasted less than eight hours but came just 24 days after a four-month closure for slip repairs.

Tracey Rissetto, chairwoman of the Automobile Association's Northland Council, said the announcement showed the government understood how badly the region needed a resilient four-lane highway.

The government's approach to building the Northland Expressway was similar to that used for the Waikato Expressway, she said.

"That was one project broken into different phases. That enabled contractors to get themselves the resources and capacity they needed. It meant they had ongoing work, and there's definitely economies of scale when you look not only at the contracting work, but also the design work and consents."

But Rissetto said the "pinch point" would be the Brynderwyns.

"I appreciate that the section from Warkworth to Te Hana is shovel ready, it's got all the consents ready to go, but the road over the Brynderwyns has only got a seven-year life span, and as we've seen recently, that life span could include a lot of closures. So that's where we'd like to see the priority when it comes to the planning and design stage."

The road over the Brynderwyns has been repeatedly closed during the last 18 months due to bad weather and slips. Photo: Supplied / NZTA

Rissetto's other reservation was around the use of a public-private partnership (PPP), because that could mean more highway tolls in Northland.

Northland was already the only region in New Zealand where motorists had to pay a toll to use State Highway 1, she said.

"I think there needs to be an overall discussion and a policy on tolling of roads. We're pragmatic and we know there's not a lot of money in the pot, especially with the underinvestment over the past decades, but we need to have a robust discussion about what roads are going to be tolled and what aren't."

Rissetto said a four-lane highway to Whangārei would unlock Northland's economy and boost its contribution to the rest of New Zealand.

It would also save lives because studies had shown new roads were safe roads, she said.

Whangārei Mayor Vince Cocurullo said the announcement was "wonderful news" for Northland.

"Having it as one big project means that it won't be stopped by any change of government. It allows a consistent approach and makes sure that Northland is looked after for the future," he said.

"We're all very, very excited about it. We just waiting for when we can start putting the spade in the ground."

The National Road Carriers Association, which represents the nation's truckies, said the government's approach of a three-phase PPP was exactly what the organisation had been calling for from successive governments.

Chief executive Justin Tighe-Umbers said an ongoing pipeline of work, with the scale to attract infrastructure companies to commit to investing in equipment and people to deliver a quality transport network, was what was needed to grow New Zealand's economy.

"As we saw last weekend the route into Northland is vulnerable and this announcement will be welcomed by our members and the wider Northland business community. Combining the projects into a single corridor will mean less time and money spent on procurement, design and supporting project management."

Transport Minister Simeon Brown said the approach could shave 10 years off the expressway's completion date.

The lack of resilient transport connections between Northland and the rest of the country had for too long been a handbrake on the region's economic development.

Brown said the previous government's decision to stop planning a replacement for State Highway 1 over the Brynderwyns had left Northland more vulnerable, and a significant amount of work was now required to get the project back on track.

The Northland Expressway would be treated as a single project, divided into three phases: From Warkworth to Te Hana (just north of Wellsford); Te Hana to Port Marsden (around the Brynderwyn Hills); and Port Marsden to Whangārei.

"Taking a corridor approach means NZTA will avoid multiple procurement processes. It will also deliver integrated design, construction, maintenance and operations across the entire Northland Expressway, and allow greater efficiencies through scale to deliver the project up to 10 years faster than traditional approaches," Brown said.

The government would also consider law changes to accelerate delivery and provide increased certainty for delivery partners.

Options being considered included changes to the Public Works Act, he said.

"The Northland Expressway is one of the largest infrastructure projects in New Zealand's history. We are considering a wide range of funding, financing, and delivery tools to get this project completed as soon as possible."

The project's cost has yet to be estimated. An investment case will be considered by Cabinet later this year.

This story was originally published by RNZ