Peel police are asking for witnesses to step forward after a hit-and-run overnight left a 23-year-old woman in critical condition.

Lindsay Tamminga was walking with a friend at the time she was hit late Thursday, near Creditview Road and Kenninghall Crescent, south of Highway 401.

"The impact was a pretty hard impact," Const. George Tudos of Peel police told CTV News, saying Tamminga was thrown quite a distance.

She was initially taken to a Mississauga hospital for treatment of serious head injuries, but was later transported to a trauma unit in Toronto.

According to witnesses, a dark-coloured sedan fled the scene. Police said the vehicle will have front-end damage as a result of the collision.

"Police are asking staff at all area automobile repair shops to be on the lookout for this vehicle, as the driver or owner may attend to repair the damage caused by the collision," they said.

Police also asked the driver to seek legal counsel and make arrangements to surrender themselves.

Anyone with information about the accident or the whereabouts of the vehicle is asked to call police at 905-453-2121, ext. 3710. They can call Crime Stoppers anonymously at 1-800-222-TIPS (8477).