Qld teenagers charged over school 'attack'

Two girls have been charged after they allegedly assaulted a police officer at a Brisbane high school.

Three girls allegedly trespassed on the grounds of the Cleveland District State High School about 2.45pm on Wednesday.

One of the girls, none of whom were current students, abused and shoved a student and then punched a 34-year-old man when he intervened, police said.

While she was being restrained, another armed herself with a stick and threatened the on-site police officer before two members of the trio were taken into custody.

"While students and teachers were unharmed during the incident, our school-based police officer sustained some minor injuries," principal Paul Bancroft said.

"Guidance officers are providing counselling and support to anyone who witnessed the incident."

The two girls, from Dunwich on Stradbroke Island and aged 12 and 14, have each been charged with trespassing, seriously assaulting police and obstructing police and will be dealt with under the Youth Justice Act.