A semi-truck crash has shut down a northbound lane of the Trans-Canada Highway in Mill Bay.

Drive BC called the crash a "major vehicle incident" on the highway at Deloume Road.

Details of the crash are unclear, but Drive BC said drivers should expect "heavy delays and congestion" in the area.

South Cowichan Community Policing reported on Twitter that a semi truck had flipped on the highway, losing a load of lumber, in a multi-vehicle crash.

Pictures from the scene showed the overturned truck as crews assessed the damage.

No estimated time of reopening was available.