Emergency services were called to the park about 12.45pm on Wednesday.Nine News reported the five-year-old was with his family when he stood close to the horse.
It is believed the incident took place near the Robertson Road Gate,which is across the road from the Centennial Parklands Equestrian Centre.
The boy was taken to Sydney Children’s Hospital,Randwick,in a serious but stable condition.
Centennial Parklands includes a track for horses that runs parallel to the pedestrian path in a loop around the park.
Signs at the entrance to the horse track read:“Caution:Active horse track”.
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