SH20 May Rd overbridge at about 3.50pm. Photo: Screenshot / Waka Kotahi NZTA
There are severe traffic delays on State Highway 20 after an overheight vehicle hit the Waterview tunnel.
Two northbound lanes were closed.
Waka Kotahi NZTA said crews were inspecting the damage to the tunnel.
Long queues were forming as one lane only remained open.
People were asked to delay travel or choose an alternative route.
Earlier three of four northbound lanes had closed because of a serious crash.
They reopened about midday though Waka Kotahi warned delays would take time to ease.