The driver of the vehicle, the boy's mother, was taken to Wimmera Base Hospital with a suspected spinal injury but was later discharged.

​Earlier

A WOMAN is in a critical condition and her 14-year-old son has been airlifted to hospital after a crash about 12 kilometres north of Horsham.

A Dimboola family of five was travelling along Blue Ribbon Road in a grey Holden Commodore when the female driver lost control of the car on Tuesday afternoon.

The woman, 34, was taken to Wimmera Base Hospital with a suspected spinal injury.

The son was travelling in the back seat and was airlifted to the Royal Children's Hospital with leg and pelvic injuries.

Two other children, aged 3 and 4, sustained minor injuries.

 A man, 35, was in the front passenger seat and also had minor injuries.

The three were taken to Horsham's Wimmera Base Hospital for treatment.

Horsham Highway Patrol Leading Senior Constable Heath Martin said the cause of the crash was unknown but investigations were ongoing.

"The vehicle was travelling south along the Blue Ribbon Road towards Horsham and the driver's lost control - we don't know why yet," he said.

"The vehicle has rolled at least once and come to rest."

Police, State Emergency Service and Country Fire Authority crews and paramedics attended.

Leading Sen Const Martin urged anyone who witnessed the crash to call Horsham police on 5382 9200.