Police are advising motorists to expect lengthy delays following a crash just outside the Johnstones Hill tunnel in Waiwera.

Around 4.49pm, a truck travelling south has collided with a van, leading to both north and southbound lanes being closed.

One person has sustained moderate injuries and is being treated at the scene. The incident has blocked both northbound and southbound lanes, causing delays.

Waka Kotahi crews and emergency services have worked to clear the crash and re-open the road as quickly as possible.

SH1 is now fully open again between Orewa and Puhoi. Expect delays as congestion eases through the area.