UPDATE 12:40 pm:

The crash site has been cleared, and the highway is now open to northbound traffic.

Drivers are asked to take care while driving this section of the until queued traffic clears and congestion eases. Ongoing travel delays can be expected.

12.10pm - State Highway 1 Johnsonville closed to northbound traffic due to crash:

Drivers heading north out of Wellington on State Highway 1 are warned to expect delays as emergency services attend a crash near the State Highway 1 Johnsonville offramp.

The highway is currently closed to northbound traffic - Police have confirmed a vehicle towing a caravan has rolled just before the Johnsonville offramp.

Drivers are asked to delay their travel, avoid the area, or use an alternative route until the incident is resolved and the crash site is cleared.

The highway’s southbound lanes remain open.

Ongoing congestion and travel delays can be expected. Updates on the highway’s status can be checked online.

Highway conditions - Wellington (external link)