Teen charged over SA school stabbing

A high school student has been charged with serious assault, accused of stabbing a classmate at their campus in the South Australian Riverland.

The 18-year-old woman allegedly attacked the 17-year-old girl with a knife at Renmark High School on Tuesday afternoon, sparking a lockdown.

The alleged victim was taken to Berri Hospital in a serious condition and the 18-year-old arrested at the scene.

She has been charged with aggravated assault causing serious harm and will be flown to the Royal Adelaide Hospital because of a medical condition.

A bedside hearing is expected for Wednesday.

The state's education department said a dispute between the two students was thought to be behind the incident, which "did not represent a specific threat to the wider school community".

The lockdown was lifted later on Tuesday, with students allowed to go home.

Renmark High School is looking at whether it needs stricter security measures.

"We share your shock at the event, which we are treating with the utmost seriousness," Principal Mat Evans said in a letter to parents.

Counselling will be available for staff and students.