A 30-year-old woman is in life-threatening condition after an overnight hit-and-run downtown.

Toronto police responded to a collision in the area of King Street West and Spadina Avenue on Thursday at around 3:15 a.m.

Police said a female pedestrian, believed to be in her 20s, was struck by a vehicle travelling at a high rate of speed and was rushed to a trauma centre in critical condition.

Police have not yet identified the victim.

The vehicle, police said, briefly stopped after the incident and then fled the scene.

"(The vehicle went) southbound and, from what we understand, at a high rate of speed. So they were fleeing the area. They knew exactly what happened and they were fleeing," Sgt. Murray Campbell told reporters at the scene.

Spadina and King hit-and-run

No suspect information about the driver has been released.

Police, however, describe the involved vehicle as a light-coloured Mercedes convertible with front-end damage. They added that the roof was folded down at the time of the crash, so the damage will be noticeable.

"As you can see, there are some vehicle parts that are left at the scene here. As part of our investigation, we'll be following up with the vehicle parts to try and identify them," Campbell said.

Southbound lanes on Spadina Avenue were closed early this morning for the investigation but have since reopened.

Police are asking anyone with information or dash camera footage to contact them at 416-808-1900 or Crime Stoppers anonymously.