Police want a motorist who chased a vehicle that mounted a footpath and struck a cyclist to come forward.
Christchurch police said they are keen to talk to the driver of a car that made a u-turn and followed a station wagon after it ploughed into three people on New Year's Day.
The trio were walking and cycling about 1.40am on Prestons Rd when a two-tone silver and white station wagon stopped suddenly and reversed, mowing down the group.
The car hit the person on a bike throwing the victim several metres. The bicycle was dragged underneath the car for around 100m.
Police say a second car travelling in the opposite direction was seen to do a u-turn and follow the station wagon.
Police want the driver to come forward saying the person may have witnessed the collision and provide vital clues about the identity of the hit-and-run driver.
They also wanted to talk to anyone else who may have information that would help identify the driver of the station wagon.
They are asked to call Senior Constable Wayne Stapley on (03) 374 1700.