One person was assessed at the scene and taken to Christchurch Hospital in a critical condition.
St John said its crews were still at the scene with a second patient in a moderate condition. There was no indication as to whether they would need to be taken to hospital.
A collision between a cyclist and a car in Selwyn has closed roads. Photo / Google
Police said the road would be closed, with diversions in place, and motorists should avoid the area.