Two people have died following a crash on Tunnel Road in Christchurch last night.

The crash, involving two cars and a motorcycle, was reported to police just before midnight.

A St John spokeswoman said ambulance officers treated and transported four patients to Christchurch Hospital – two in a critical condition and two in a serious condition.

A police spokeswoman said investigations into the circumstances of the crash are under way.

Tunnel Road remains closed in both directions, from the intersection with Ferry Road to Bridle Path Road. 

Motorists are asked to follow the diversions that are in place.