Timeline for reopening SH1 over Mangamukas in Northland revealed on Friday

Drainage work being carried out on Mangamuka Gorge, on State Highway One, south of Kaitaia

Waka Kotahi will reveal “a timeline to reopening” State Highway 1 over the Mangamuka Gorge on Friday as the road undergoes a $100 million repair job.

But the transport agency has already spread the good news about a temporary reopening of SH1 through the Brynderwyns in time for Easter.

The critical portion of SH1 via Mangamuka Gorge has been shut since heavy downpours in August last year caused slips above and below the highway. The closure severed the arterial route into Kaitāia and the Far North that had not long before reopened following a previous shutdown.

Waka Kotahi would not reveal exactly what would be brought to light on Friday or a potential opening date for the route.

“We expect to share more information of a timeline to reopening SH1 Mangamuka Gorge by the end of the month,” Waka Kotahi regional manager maintenance and operations Jacqui Hori-Hoult said.

Mangamuka Gorge’s SH1 closure has added huge amounts of extra travel time for truckers and others travelling into the Far North who are having to use the alternate SH10 around the Far North’s east coast.

Installing temporary piles in major Mangamuka Gorge SH1 slip

Northland Mayoral Forum chairman Vince Cocurullo said recently the SH1 Mangamuka Gorge closure was costing truckies taking freight north to Kāitāia from Auckland an extra $1000 each way on their journeys.

The Mangamuka Gorge state highway closure has added half an hour to car trips into the Far North and added major traffic loading on alternate SH10.

The closure has been exacerbated by Cyclone Gabrielle reopening old wounds further south on SH1 over the Brynderwyns, which had restricted access since February 11.

The $100 million for the Mangamuka Gorge repairs was aimed at restoring the route to its original condition.

Mangamuka Gorge was also hit by major slips in July 2020 with repairs taking almost a year and costing $13.8 million.

Work on the road through the Mangamuka Gorge is being done in three phases. The first will protect the road from further damage, the second stage will fix slips and return the route to its original condition, and the third will future-proof the road so it can withstand weather events.

There have been fears since Cyclone Gabrielle that Mangamuka Gorge repairs would suffer, with attention instead shifting to SH1 over the Brynderwyns, and putting huge pressure on alternate bypass diversions over Whangārei and Kaipara District Councils roads.

The Brynderwyns will be open over Easter for two-way traffic for the first time since Cyclone Gabrielle, then close again for permanent repairs from April 17.

Roading repairs progress over SH1 on Mangamuka Gorge