The huge increase in traffic on State Highway 10 due to the closure of New Zealand's main north-south highway over the Mangamukas is causing serious crashes, a Far North-based local government leader has warned.
"I'm pretty concerned about what's happening up in the north there," Colin 'Toss' Kitchen MNZM, a Far North-based Northland Regional Councillor said.
"Since the Mangamuka Gorge has closed, there's been a hell of a lot of traffic (along State Highway 10) and I'm just observing the way people are driving, stupid overtaking, all that sort of thing," Kitchen said.
People needed to take more care on the overloaded alternative state highway route north, Kitchen said.
About 20km of SH1 is closed over the Maungataniwha Ranges south of Kaitaia, the road known locally as the Mangamukas.
The closure came in July after eight slips - the biggest of which is still being repaired - following torrential rain.
It is blocking one of the Far North's two major accessways and interrupting the main north-south travel route between Whangārei and Kaitaia. Traffic is now being forced to access the Far North via SH10 to the east which skirts through the Bay of Islands.
State Highway 10 traffic had increased tenfold since the Mangamukas closure, Kerikeri Volunteer Fire Brigade chief fire officer Les Wasson said.
"It's quite hideous," he said. "The traffic along State Highway 10's gone berserk."
State Highway 1 at Mangamuka is expected to be open over Christmas/New Year for holiday traffic - but to light vehicles only, with stop-go traffic management in place on the winding mountain road.
It's then expected to shut again with two-lane reconstruction and realignment, which will include digging into the hill beside the road.
Wasson said trucks that would usually have gone over the Mangamukas were now also travelling SH10.
Traffic congestion started about 6am and continued until 10pm. It's mind boggling," Wasson said. "And it's not going to ease any time soon."
Roadworks at Puketona and Waipapa were compounding congestion.
It would be only six weeks until major summer holiday traffic added to the situation. The influx would be bigger than normal with Kiwis from Auckland and beyond to holidaying domestically due to Covid-19.
"We've already seen that happening over Labour Weekend with lots of vehicles towing boats heading north," Wasson said.
Increased traffic was starting to result in SH10 road surfaces breaking down in places.
Kitchen, who is also a 50-year-plus Kaitaia Fire Brigade volunteer, said the situation was putting local emergency services under pressure.
"The effect of the Mangamukas is putting pressure on (local) emergency services," Kitchen said. "It is concerning."
Kitchen is one of the area's emergency response volunteers who attend the SH10 fatal crashes.
He said police booze buses should be brought back to the area. This will be considered at the Northland's regional transport meeting in early December.
"A lot these crashes are speeding and alcohol-related," Kitchen said.
The biggest Mangamuka road slip saw about 7000cu/m of material fall away beneath the road, leaving its surface unsupported to the centre line. The road climbs to 383m over the Maungataniwha Ranges.
It climbs to 383m and is known as one of the most winding, twisty and hilly parts of New Zealand's roughly 1000km-long SH1. It was built in the 1920s and sealed in 1961.
July's closure came after torrential downpours, with some parts of Northland getting 200mm of rain in just 12 hours.