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Northland's main road link with Auckland and the rest of New Zealand is being interrupted throughout today by a 13-hour closure of State Highway One over the Brynderwyn Hills, for emergency resurfacing.
The Transport Agency is urging motorists and truck drivers to allow for delays of between 30 minutes and an hour, via circuitous detours around the hills, until the road is due to reopen at 7.30pm tonight.
Although traffic will be directed to established alternative routes around both sides of the hills, the agency says these are slower and about 20km longer than the normal link between Brynderwyn and Waipu.
Northbound traffic will be directed to the western side of the hills on the way up to Whangarei, via State Highway 12 to Paparoa and then over local roads to Oakleigh, where it will rejoin SH1.
Vehicles heading towards Auckland will be diverted through Waipu Cove and Mangawhai before rejoining the main highway at Kaiwaka.
The Transport Agency says both alternative routes are established detours, rather than "makeshift" trails, and easily capable of handling big trucks.
But it expects about 4000 vehicles along each route, so is asking drivers to consider making only essential trips to ease delays.
Acting regional manager Tommy Parker said the resurfacing work, near the southern end of the hill route, was being done before Labour Weekend to prepare for large volumes of holiday traffic.
The work follows the opening of potholes after a wet winter, and the agency is also taking the opportunity to erect a 30m safety guard rail between the road and a waterfall.
Road Transport Association northern manager Raywin Head said she had sent out two rounds of notices to alert her members, and some truck operators were rearranging delivery schedules to minimise disruption.
An agency spokesman said the repair site was too remote for adequate lighting to be provided for the work to be done safely enough at night.
