It happened at around 3.20pm on Dufferin Street, near Wellington Street.
Images from the scene showed two badly damaged vehicles on the roadside grass, one of which was on its roof.
Police said someone may have been ejected and pinned in the crash.
One person has been taken to hospital. Police said an officer may also have been injured in the collision.
There were two women who were also injured, police said.
Police and fire brigade are at the scene.
Dufferin Street is closed between 16th Side Road and 17th Side Road as crash investigators investigate the scene.
