Police are searching for a vehicle with a child inside which has been submerged in the Hawkesbury River.
About 10.45am today, police and Ambulance Paramedics were called to a boat ramp at a caravan park on River Road, Lower Portland.
Police were told a vehicle was reversing a boat and trailer into the river, when the vehicle slid into the water with a young boy inside.
The vehicle has not yet been located. Police from Hawkesbury Local Area Command, PolAir, Ambulance Paramedics, and the SES remain on scene searching for the vehicle.
It is believed the vehicle has been pushed downstream by a strong current, NSW Police say.
Police Divers are on the way. No further information is available at this stage.
Police are urging anyone with information in relation to this incident to call Crime Stopers.