A teacher was assaulted and 50 cellphones were stolen at Sea Point High School on Wednesday after armed robbers scaled the school fence and invaded a packed classroom while students were writing exams.

The suspects are yet to be arrested.

"The circumstances surrounding an armed robbery are being investigated following an incident on Wednesday around 10.10am at a high school in Sea Point," said Western Cape police spokesperson Lt-Col Andrè Traut.

"Two armed men entered a classroom, threatened a teacher and pupils and fled with cellphones."

Exams continued as scheduled on Friday and the school has made counselling available to all students. The teacher who was assaulted has received medical treatment.

"We hope the SAPS will use the camera footage to identify the suspects and ensure they face the full might of the law," said provincial education MEC Debbie Schäfer. "I have also requested that this case be added to the watching brief lists and my office has already made contact with the Sea Point SAPS," said Shäfer.

"I am genuinely concerned that criminals have become so brazen that they enter school premises on a busy road, in broad daylight, and that not even a strong security presence, CCTV footage or fencing serve as a deterrent."