A woman in her sixties was found dead in a car that was stuck on rocks in a river just yards from Niagara Falls on the US-Canadian border on Wednesday, police said.

The discovery of the car with a body inside it triggered a dramatic Coast Guard helicopter recovery of the woman's remains, although the car remained in the rapids after the body was recovered.

Police in the city of Niagara Falls were alerted around midday to the presence of a black car almost completely submerged in the Niagara River, some 50 yards from the edge of the world-famous waterfall.

"The water levels were lowered by the Power Authority, drones and the Niagara County Sheriff helicopter were used to determine any vehicle occupants. One body was observed in the driver seat," New York State Park police staid in a statement.

The woman's body was pulled from the vehicle by the Coast Guard, and she was pronounced dead on the scene.

An investigation has been launched to determine how the car ended up in the Niagara River, between a road bridge and a pedestrian bridge in the town.