Police officers and paramedics from the Isle of Wight Ambulance Service are currently attending the incident, which has involved a Black Mitshubishi 4×4 and a White Mercedes Vito van.
Two fire crews from Newport Fire Station have been called to the scene to extricate the occupants of the van, who are understood to be medically trapped.
Witnesses have reported that a motorcyclist had a lucky escape in the incident, narrowly avoiding one of the vehicles.
The road has been closed in both directions between the Hare and Hounds and Lime Kiln Shute. Motorists are advised to avoid the area.
UPDATE: The Downs Road has now reopened in both directions. At least one casualty has been taken to St Mary’s Hospital, however is not thought to have been seriously injured.
The Mercedes Van is understood to have been travelling towards Newport when another vehicle cut in front as it turned into Newport Shute.
The driver of the vehicle was extricated by the Isle of Wight Fire and Rescue Service.