Police are investigating the circumstances surrounding a boating accident at Lake Macquarie this afternoon.

Emergency services were called to Ada Street, Belmont, about 4.45pm (Saturday 7 February 2015), responding to reports that a child had fallen into the lake while sailing.

NSW Ambulance Paramedics rendered first aid to the boy before he was taken to John Hunter Hospital. He is reported to be in a critical condition.

The child was wearing a life jacket at the time.

Police from Lake Macquarie Local Area Command are speaking with witnesses at the scene, including a second boy who was also on the boat.