A five-year-old boy suffered a broken ankle after he was allegedly knocked over by a car in Mosgiel on Saturday.

Police say the incident happened outside his Murray St home about midday.

"The driver stopped and spoke with the boy and his mother immediately afterwards but Police have yet to identify him."

The driver is described as aged possibly in his late 30's, of a stocky build and balding.

Police say he was driving a silver, four door vehicle.

If anyone has any information on this matter, contact Constable Darrin Healy via Dunedin Police (03) 471 4800 or the organisation Crimestoppers on 0800 555 111.