Update: Police say fatigue could have been a factor in a head-on crash on the Princes Highway that hospitalised three people, including a child.
Emergency services responded to the crash at Pomborneit around 1pm on Monday and airlifted a school-aged Portland girl to the Royal Children's Hospital.
Colac Highway Patrol Senior Constable Paul Barker said police believed a westbound Subaru drifted into the wrong lane and collided with an eastbound van.
He said the child was travelling in the Subaru in the front passenger seat and had likely suffered a broken arm.
Paramedics took the sedan's driver, a 50-year-old Portland woman with multiple injuries, to University Hospital Geelong in a stable condition.
A road ambulance also took the driver of the van, a 38-year-old Melbourne man with minor injuries, to the Geelong hospital.
Five emergency vehicles responded to the incident and the highway closed for some hours with detours in place.
"It's extremely lucky that no one was seriously injured or killed in this collision," Senior Constable Barker said.
"Other road users should be aware if you are tired take an actual break."
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