A 14-year-old girl has been refused bail after she allegedly stabbed a fellow student in the bathroom of an Adelaide school.

The girl faced the youth court on Thursday charged with aggravated intentionally causing harm over the incident, which police say took place during school hours on Wednesday.

A prosecutor told the court the victim had been standing at a hand basin in the bathroom when she felt a sharp pain through her upper back. The girl was left with a one-centimetre laceration to her upper right back region.

A bail report has been ordered and the accused girl was remanded in custody to appear in court again next week.

The girl’s parents and aunt were present for the hearing but did not make any comment outside.

Wednesday’s incident was the second stabbing at a South Australian school in little more than a week.

On 24 July, an 18-year-old student was alleged to have stabbed a 17-year-old girl in the back at Renmark high school.