The Isle of Wight Fire and Rescue Service have mobilised appliances from Newport, Shanklin and Sandown to the incident on the main A3056, where a car has left the carriageway.
The Isle of Wight Ambulance Service has also dispatched a number of assets to the scene of the crash, which has happened on the bend by Branstone Farm.
A male driver and a female passenger are being extricated from a small hatchback by fire crews.
Hampshire Fire Control have said they received a 999 call reporting the single-vehicle collision at 22:23.
Police have closed the road to traffic in both directions, between Watery Lane and Branstone Cross, with motorists having to divert locally.
The road is expected to remain closed for several hours.
UPDATE @ 23:10 – The Dorset and Somerset Air Ambulance has now landed in a field near the scene.
Both casualties have been extricated and are being assessed by flying doctors.
1 person is expected to be flown to Southampton’s Major Trauma Centre.
UPDATE @ 23:39 – Fire crews have now stood down from the incident having successfully freed the 2 individuals from a Ford KA, which is understood to have collided with a tree.
Police remain on scene and a hard road closure is being put in place by Island Roads.
UPDATE @ 00:12 – 1 person has been airlifted to Southampton General Hospital for specialist treatment.
The main road remains closed between Watery Lane and Branstone Cross.
UPDATE SUNDAY @ 07:00 – The main road has now reopened to all traffic.
UPDATE @ 13:25 – Police have issued a witness appeal after a male in his 20s and a female in her 30s were hospitalised with serious, but not life-threatening injuries last night.