Waitangi weekend traffic: Auckland motorists told to expect delays travelling north on State Highway 1

Motorists travelling through State Highway 1 northbound in upper Waiwera are being told to expect delays as Aucklanders escape the city for the long weekend.

"Due to high traffic volumes, SH1 is currently congested prior to Johnstones Hill Tunnels. Please expect significant delays while travelling through this area," Waka Kotahi said on Twitter.

Meanwhile, after clearing a steep slip from the treacherous over the past week, SH12 at the Brynderwyn Hills has been reopened for northbound vehicles between 8am and 8pm on Saturday.

"For safety reasons the road will remain closed overnight, from 8pm to 8am, and conditions will be re-assessed each morning, with safety being our top priority," Waka Kotahi said.

The transport agency said they will change the direction of the traffic flow on Monday to allow southbound vehicles on SH1 for motorists travelling back to Auckland.

On Tuesday, traffic flow will revert back to northbound until further notice.

Waka Kotahi said contractors and geotechnical engineers will be onsite throughout the weekend to monitor any additional slips or ground movement. The road could close at short notice if it becomes unsafe to use.

"Temporary speed restrictions will be in place and Waka Kotahi urges motorists to use caution and drive to the conditions."

If SH1 closes, light vehicles will need to use the detour via Mangawhai and heavy vehicles will need to use SH12 and the SH14 state highway, the agency added.

For a full list of current closures on the network, visit Waka Kotahi's journey planner.