Emergency services were called to the crash in Riccarton Rd, near Mona Vale Ave, about 3.30pm on Tuesday.
A police spokesperson said "initial indications suggest serious injuries".
Riccarton Rd was blocked off between Deans Ave and Mona Vale Ave, and reopened just before 6pm, police said.
The serious crash unit was also called to the scene.
Police are making inquiries to determine the circumstances of the crash, the spokesperson said.
“Christchurch police would like to acknowledge the members of the public who provided assistance at the time of the collision,” the spokesman said.
A St John spokesman told Chris Lynch Media they responded with an ambulance and two rapid response vehicles.
One person was transported to Christchurch Hospital in a critical condition.
