Northland Expressway preferred routes: New road over Brynderwyn Hills to be built

• A new route to replace SH1 over the slip-prone Brynderwyn Hills will be built just east of the existing highway, not well to the west as originally planned
• Transport Minister Chris Bishop won't commit to a cost or timeline, but says the full Northland Expressway will be a multi-billion-dollar project
• Work on another section of the expressway, from Warkworth to Te Hana, is expected to start next year and be completed in 2032
• The completed expressway is likely to have two more toll points, making a total of three between Auckland and Whangārei

A replacement for State Highway 1 over Northland's notorious Brynderwyn Hills will be built just to the east of the current road - a major change from the original plan of building the new four-lane highway well to the west of the slip-prone hills.

This morning Transport Minister Chris Bishop announced NZTA Waka Kotahi's preferred route for the Northland Expressway, stretching 100km from the motorway's current endpoint at Warkworth all the way to Whangārei.

The biggest surprise is that NZTA has dropped its earlier preference for a route that would have skirted around the western side of the troublesome Brynderwyn Hills.

Instead, the new route will, like the current highway, go over the top of the Brynderwyns, but to the east of the existing route.

Bishop said the Brynderwyn Hills section was highly challenging, due to the steep terrain and unstable geology.

"Alternative options looked at western routes but following further investigation, NZTA has reassessed and found a near-east alignment close to State Highway 1. This is a more direct route with more predictable geology that can be managed through engineering design," he said.

Bishop would not commit to a timeline or cost for the project, saying he wanted to avoid "back-of-the-envelope" estimates.

However, the full Northland Expressway would be a "multi-billion-dollar" project, he said.

Last year the Infrastructure Commission warned the expressway could be one of the most expensive infrastructure projects in New Zealand history, consuming $1 of every $10 of Government infrastructure spending over the next 25 years.

Also announced this morning were the preferred routes for two other sections of the Northland Expressway.

Bishop asked Northlanders for patience, saying the expressway would be built in stages over many years.

The first section out of the blocks would be the 26km stretch from Warkworth, the expressway's current endpoint, to Te Hana, Bishop said.

It would bypass the summertime traffic jams of Wellsford and be built mostly to the east of the current highway.

Bishop said that section was already consented with procurement now underway.

Work was due to start next year with completion expected in 2032.

Earlier this year, Italian company Webuild confirmed it would bid to build and operate the Warkworth-Te Hana section as a public-private partnership.

The section over the Brynderwyns would be built after that, Bishop said.

The section of highway from the northern side of the Brynderwyns to Port Marsden Highway, at Ruakākā, would run west of the existing highway.

A preferred route for the northernmost section, a notoriously crash-prone stretch of highway between Ruakākā and Whangārei, had yet to be settled.

Bishop told reporters there would "almost certainly" be a toll on the Warkworth to Te Hana section, and possibly also on the section north of the Brynderwyns.

That would make a total of three tolls between Auckland and Whangārei.

He said NZTA would start engaging Thursday with landowners who could be affected by the new expressway.

He expected the precise route would be confirmed in August or September.

Also taking part in this morning's announcement at a lookout atop the Brynderwyns were Whangārei MP Dr Shane Reti, Northland MP Grant McCallum, and Regional Transport Committee chairman Joe Carr.

Reti said the Northland Expressway would be a game-changer for the region, boosting economic growth and creating job opportunities.

He also looked forward to a wider, safer highway just south of Whangārei, which until recently had one of the country's highest death rates per kilometre.

McCallum said the expressway would make up for generations of under-investment in the North.

"It will bring places like the Bay of Islands and Kaitāia closer to customers and visitors, who love coming up here, but they do get frustrated by our roads," he said.

Carr, who has long lobbied for an alternative route east of the current highway, said the Brynderwyn closures of 2023-24 had cost the region about $200 million.

Harder to quantify was the reputational damage suffered by Northland, with some businesses wary of investing in a region without reliable road connections to the rest of the country.

Regional Development Minister Shane Jones said Easter weekend's partial closure of State Highway 1 over the slip-prone hills highlighted the need to get work underway urgently.

He said the new expressway would be designed to better withstand severe weather, keeping people and goods moving and reducing travel times between Northland and Auckland.

Ironically, both the previously favoured routes west of the Brynderwyns would have passed through a Maungaturoto farm owned by Northland MP Grant McCallum.

Had either of those routes been chosen, McCallum said he would have stepped back from any negotiations and left that to his family.

Plans for a new route around the Brynderwyns were put on ice in 2017 but revived with urgency in the wake of Cyclone Gabrielle in early 2023, when the highway was closed on-and-off for months due to slips and reconstruction.

During the closures, traffic between Auckland and Northland was forced to use narrow back roads via Waipū, or the much longer State Highway 14 around the west coast.

Even the $85 million repair job carried out on the unstable south side of the Brynderwyns in 2024 is expected to last only another seven to 10 years.

A slip triggered by Cyclone Tam during Easter weekend blocked one lane and reportedly damaged a car.

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