One person is critically injured in an crash that has closed an Auckland road.

Police said "major delays" are expected following the crash on Panmure's Lagoon Drive.

Emergency services were notified of the crash at 7.20am on Friday morning.

"At this stage one westbound lane remains open and diversions are in place for all eastbound traffic.

"One person is in critical condition, and emergency services remain on the scene.

"Heavy delays are expected and motorists are advised to seek an alternative route."