The driver, a 42-year-old female ambulance technician, and the patient, an 88-year-old man, were pronounced dead at the scene.
A male crew member and a male relative of the patient remain in hospital both in a serious condition.
Police are continuing to appeal for witnesses following a collision involving an ambulance and a car in the New Forest.
A driver arrested in connection with the incident on the A337 yesterday morning has been bailed until July 29.
The 25-year-old, who was driving a blue Seat Alhambra, was arrested on suspicion of causing death by driving without due care and attention.
Both the car and the ambulance were heading north on Lyndhurst Road when, for reasons yet to be established, the ambulance came off the road and hit a tree.
Two people have died, with two others seriously injured after an ambulance crashed into a tree in Hampshire. Andrew and Sangeeta linked to Martin Dowse in the New Forest.
South Central Ambulance Service have released this statement:
"A double crewed ambulance belonging to South Central Ambulance Service NHS Foundation Trust was involved in a collision with a tree on the A337 Brockenhurst to Lyndhurst road at 09.35 this morning.
"The ambulance was en route to Southampton General Hospital at the time of theincident conveying an elderly male patient. The patient was accompanied in theambulance by a relative.
"A female member of the ambulance crew and the elderly male patient were pronounced dead at scene.
"A male relative of the deceased patient was collared and boarded at scene and has been conveyed to Southampton General Hospital by land ambulance.
"A male ambulance crew member has been airlifted to Southampton General Hospital by the Hampshire and Isle of Wight Air Ambulance (Helimed 56).
"South Central Ambulance Service NHS Foundation Trust is conducting appropriate welfare checks with the families of all involved.
"The road is closed until further notice and motorists are asked to avoid the area. Diversions are in place."
Two other cars were involved in the incident apart from ambulance.
Police will not give further details at this stage and will not identify the people involved for at least 24 hours.
A337 in both directions closed due to accident investigation work between B3055 Balmer Lawn Road (Brockenhurst) and Beechen Lane (Lyndhurst). Expect delays.
The road is expected to remain closed until this afternoon for investigation works and recovery. Diversion - a lengthy diversion via the A35.
Gwyn Williams was over taken by the ambulance shortly before the crash in the New Forest and told ITV Meridian what he saw.
He had been driving along the A336 between Brockenhurst and Lyndhurst in the New Forrest.