Northland Expressway preferred routes: Government eyes new road over Brynderwyns, rather than bypass

The highway through the Brynderwyn Hills has been repeatedly closed since bad weather in 2023. Photo / Michael Cunningham

• The Government has mapped the preferred route of the new Northland Expressway, tipped to be one of the country’s most expensive infrastructure projects.
• The Government is opting for a new route over the Brynderwyn Hills, to the east of the current state highway.
• The first section of the expressway has already been confirmed.

The preferred route for the Northland Expressway – tipped to be one of the country’s most expensive infrastructure projects – has been revealed, with ministers eyeing a new highway over the Brynderwyn Hills rather than a bypass.

NZ Transport Agency Waka Kotahi (NZTA) has investigated options to the slip-prone Brynderwyn Hills state highway, including two bypass routes to the west.

Transport Minister Chris Bishop revealed today the earmarked route will go from Warkworth east of State Highway 1 and over the Brynderwyn Hills, then through to Whangārei.

“The Brynderwyn Hills is a very challenging section due to the steepness of terrain and quality of the geology.”

Bishop said NZTA had considered alternative western options but after reassessment, had found “a near east alignment close to SH1”.

“This is a more direct route with more predictable geology that can be managed through engineering design.”

Bishop told The Mike Hosking Breakfast this morning that procurement for the first section - continuing the current expressway north of Auckland from Warkworth to Te Hana - would begin mid to late next year.

He could not yet say the timeline for the section encompassing the Brynderwyns, but answered “absolutely, yes” when Hosking, 60, asked if the overall project would be completed in his lifetime.

Bishop acknowledged costs could increase over the project’s timeline, but said a lot of work was being done to avoid that.

“This is undoubtedly a challenging project ...[but when complete] the Northland Expressway will be transformational, like the Waikato Expressway.”

‘More resilient transport’

The Brynderwyn Hills, about 45km south of Whangārei, have been subject to ongoing closures since severe weather in early 2023.

Last year, the highway was closed for about four months as NZTA repaired numerous slips.

Over Easter, a landslip on Brynderwyn Hills badly damaged cars and blocked part of SH1 as the Auckland and Northland regions were battered by heavy rain.

Regional Development Minister Shane Jones said the new expressway would better withstand severe weather and provide a more resilient transport network to keep people and goods moving and reduce travel time.

Recent heavy rain caused a slip on State Highway 1 near the Brynderwyn Hills in Northland.

“This transport infrastructure is a key point in the New Zealand First-National coalition agreement,” Jones said.

“The Northland corridor is a top priority for the Government and we are working quickly to deliver this vital connection to help Northland’s economy grow and its communities thrive.”

Once fully complete, the Northland Expressway is estimated to be one of New Zealand’s most expensive infrastructure projects.

The Infrastructure Commission has estimated the project will consume $1 in every $10 spent by the Government on infrastructure over the next 25 years. This excludes maintenance and renewals.

The Herald reported on the commission’s findings in September, including warnings from the commission that the road’s price tag would make up a large proportion of the pool of capital intended to be spent on all other central government infrastructure such as roads, hospitals, schools, defence and justice.

The roading project, one of the Roads of National Significance, will be delivered as a Public-Private Partnership (PPP).

The Government sought investors to help build the first section of the expressway at the recent inaugural Investment Summit, where attendees included firms that collectively had more than $6 trillion under management.

Regional Development Minister Shane Jones (central), flanked by Prime Minister Christopher Luxon (from left), Transport Minister Chris Bishop and former Transport Minister Simeon Brown. Photo / Mark Mitchell

At the summit, large Italian firm Webuild confirmed it would bid to build and run the first 26km section of the expressway, with the company’s head of PPPs Guido Cacciaguerra declaring to media: “The Italians are coming back”.

The expressway has been divided into three sections: 1) Warkworth to Te Hana; 2) Te Hana to Port Marsden Highway; 3) Port Marsden Highway to Whangārei.

The first section will connect the new expressway north of Auckland, which now ends at Warkworth, to Te Hana. It will include an 850m twin-bore tunnel in the Dome Valley and interchanges at Warkworth, Wellsford and Te Hana.

For section two, the preferred corridor is a new route east of SH1 between Te Hana and the Brynderwyn Hills, then weaving to the east near the current SH1 at the Brynderwyn Hills and then to the west of SH1 between the Brynderwyn Hills and Port Marsden Highway.

For Port Marsden Highway to Whangārei, the preferred option is a new road near SH1 between Port Marsden Highway and State Highway 15 Loop Rd and a widened SH1 corridor approaching urban Whangārei.

Bishop said the highway would be “a genuinely transformational” chance to boost jobs and growth in the area.

Julia Gabel is a Wellington-based political reporter. She joined the Herald in 2020 and has most recently focused on data journalism.