Dapto High School was placed in lockdown on Thursday after children from another school attempted to confront a student.
The interlopers, two boys from Kanahooka High School, attended the Cleveland Road campus about 12.45pm.
The Mercury understands students were grouped in the back paddock as police were called.
The lockdown lasted only about 30 minutes.
Police spoke to the boys and issued them with notices banning them from the premises.
Contrary to reports on social media, Lake Illawarra Police District has confirmed there were no weapons involved in the confrontation.
The Mercury has sought comment from school leaders.
Meantime, the following has been posted on the school’s Facebook page:
“Dapto High School has undergone a short lock-down procedure this afternoon. Our students and staff are safe and well. They are to be congratulated on the efficient way they followed the lock-down procedures. The authorities have been notified and are managing the situation. Sport has resumed as normal.”