Serious crash shuts down SA highway

The Augusta Highway will be closed for several hours following a serious collision at Lochiel.

South Australia Police say three vehicles collided on Augusta Highway, about 10km north of Lochiel, at about 2.40pm on Sunday.

As a result of the crash, three were airlifted to the Royal Adelaide Hospital in a critical condition, and one person with serious injuries has been taken to the Lyell McEwin Hospital.

Two people with minor injuries were treated at the Clare Hospital but have since been released.

The road is expected to be closed until 11pm on Sunday night.

Motorists have been advised to avoid the area.