UPDATE 10.24PM: Ambulance Victoria spokesman John Mullen has confirmed a woman has been flown to the Alfred Hospital in Melbourne in a serious but stable condition.
"A woman in her 30s has been flown to the Alfred with a laceration to the head and a serious arm injury.
"A male in his 40s has a head injury and is being treated at Bendigo Hospital.
"They are both in a serious but stable condition.
"It was a single vehicle accident.
"The vehicle crashed into a tree and the passenger side was pushed in."
UPDATE: 10PM: A police spokesperson has confirmed the Loddon Valley Highway has been closed between Myers Flat and Serpentine as police divert traffic around the scene.
UPDATE 9.40PM: Ambulance Victoria spokesman John Mullen has confirmed a woman had been rescued from the vehicle.
"We got the call at 8.31pm.
"The woman has just got out the car.
"It would appear both passengers have head injuries.
"They are being assessed by paramedics at the scene."
UPDATE 9.25PM: A police spokesperson has confirmed the single vehicle accident is on the Loddon Valley Highway near the intersection of the Marong-Serpentine Road.
More to come...
EARLIER: Police and emergency services are attending a crash at Serpentine with reports one person is trapped in the vehicle.
A CFA spokesperson confirmed units were attending the scene.
"There are reports someone is trapped in the vehicle," he said.
"The crews are attending now.
"The police will be dealing with it."
More to come.