Brynderwyns instability shows need for alternative, four-lane SH1 route

A slip closed State Highway 1 at the Brynderwyn Hills on Saturday, less than a month after it was reopened.

The closure of State Highway 1 at the Brynderwyn Hills from a slip on Saturday has highlighted the need to urgently replace the route with an alternative four-lane highway, according to Northland leaders.

Heavy rain caused a number of slips on the route on Saturday, before a large slip at 11am closed the highway in both directions.

It reopened at 6.30pm on Saturday under a 30km/h speed restriction and NZ Transport Agency Waka Kotahi (NZTA) continued to monitor the site over the weekend as more rain fell.

The slip came less than a month after the highway reopened following a four-month closure to stabilise it from slips, which was estimated to have cost Northland hundreds of millions of dollars.

Many locals vented on social media over the weekend, saying the route looked like it would slip any time there was heavy rain.

But Northland MP Grant McCallum said the way the road has now been designed means not all slips will close the road, just unusually large ones.

“The reason we spent $70-odd million on widening the road and improving the faces, is so that when we get slips, we’re still able to keep the road open. There were lots of smaller slips which stayed behind the barriers.”

McCallum said the design also meant the route would reopen quickly when there was a slip large enough to close the road, with slips to be expected in Northland.

But he accepted people were frustrated with the ongoing closures and he said more information about an alternative to the Brynderwyns would be announced soon.

The announcement would cover a probable timeline and financing options, which could include tolls to get the road built, McCallum said.

“I understand people are feeling really over it and just want some answers.”

Earlier this year, Transport Minister Simeon Brown said an alternative to the Brynderwyns would be built within 10 years, if not sooner.

A slip closed State Highway 1 at the Brynderwyn Hills on Saturday, less than a month after it was reopened.

On Saturday, he shared frustration at the route closing once again.

“This is incredibly disruptive and frustrating for local communities, businesses, driver, and freight operators... The Brynderwyns is a crucial connection to and from Northland for both people and freight,” he said on X, formerly Twitter.

“Significant investment has recently been made to ensure this corridor is resilient so that slips can be cleared more quickly when they happen, while our government prioritises the delivery of an alternative to the Brynderwyns as a new Road of National Significance.”

Whangārei mayor Vince Cocurullo, who spoke with Brown on Saturday, said the minister understand the pain Northland feels when the route is closed.

“He really does feel for Northland and really wants to see Northland achieve. He’s conscious that every time this closes, it’s another blow for Northland.”

Cocurullo said Saturday’s closure, less than a month after the highway reopened, was very frustrating.

NZTA contractors worked quickly on Saturday to get the Brynderwyn Hills open by 6.30pm.

“I was not expecting it to fail within one month, I was at least hoping for a year. It was disappointing.”

But Cocurullo said the repair was only ever meant to be a temporary fix while work on a four-lane alternative started. That would take at least two years for route designation and land acquisition, plus a further three years for construction.

Meanwhile, SH1 remains closed at Mangamuka Gorge, south of Kaitāia, with that route expected to reopen by Christmas, he said.

“Northland has had a really hard time over the last year and a half.”

Brynderwyns ‘worse than before’, Northlanders say

Frustrated locals vented on social media over the weekend over the poor fix of the Brynderwyns, with some saying it was left worse than before the repairs which required a four-month closure.

“They’ve made it worse than before,” one resident said to Brown on X.

“We knew it wouldn’t hold up... signed all of Northland,” said another.

One person pointed out the “fix” destabilised the slopes, cut slopes too steep and left loose soil and rocks. Another asked Brown why the slopes were not reinforced.

But Cocurullo said the work done was the best job that could be done with the budget available.

Slips in Northland are inevitable due to Northland’s geography, he said.

“This is Northland: It is a whole pile of different soils compressed on top of each other, so it’s not stable ground.”

McCallum said NZTA has been told by himself and Brown that it needs to improve its traffic management when a closure does happen.

A number of people were frustrated they had to turn around and back-track on Saturday, as signs had said the road was open when it was not.

Denise Piper is a news reporter for the Northern Advocate, focusing on health and business. She has more than 20 years in journalism and is passionate about covering stories that make a difference.