Officers have urged the driver of a silver or beige Nissan Primera to contact them following the incident, which occurred in a Cork City suburb at 5.05pm on Saturday.
The vehicle, which investigators say has a registration plate of 2002 or later — hit the 9-year-old while travelling through the Dillon’s Cross and Gordon’s Hill-Steep Rd area.
The boy suffered a broken leg and was taken by ambulance to Cork University Hospital.
A garda spokesperson said the accident could have had far more serious consequences. The spokesperson added the boy’s younger sister witnessed the accident.
It is understood the driver of the car stopped his vehicle momentarily after the crash to see what had happened. He then drove off at high speed.
Gardaí are studying CCTV footage to identify the vehicle.
“We are appealing to the driver of this car to come forward. This person knows that they struck the boy,” a garda spokesperson said.
Anyone with information can contact Mayfield garda station on 021 455 8510.