Protesting pupils set eSokheni Secondary School, in Greytown, near Pietermaritzburg, ablaze during unrest on Monday.
The Mercury understands the pupils were demanding "a more beautiful school", scholar transport and for the provincial Department of Education to provide them with breakfast, as well as the lunch it already gives them.
It is understood that two classrooms and a staff room were gutted but the rest of the school appears functional.
Education spokesperson Kwazi Mthethwa said on Tuesday that the matrics' trial exams were continuing, with a heavy police presence at the school.
But he said that teaching and learning had been disrupted and some classes cancelled.