The Department of Basic Education says at least 962 schools across the country have been vandalised and robbed since the start of the national lockdown.
In all of the incidents, administration blocks and laboratories have been targeted, and ICT (information and communications technology) equipment stolen, Basic Education Minister Angie Motshekga said on Thursday.
She added that classrooms had also been set alight by vandals.
Motshekga was briefing the media to outline the department's Covid-19 plan, to ensure that schools are ready to resume teaching and learning in a safe space.
"I will be failing my duty if I don't express my deep concern about what is happening to our schools during the lockdown," the minister said.
The Umlazi District in KwaZulu-Natal is among the worst hit, with 41 schools affected, Motshekga added.
Food meant for the school nutrition programme had also been stolen from the premises.
The minister said the department was concerned, and she appealed to the community to assist the police in nabbing the culprits.
Motshekga also welcomed the work done by the police in ensuring that those behind the vandalism and robberies were brought to book.
Gauteng is another hard-hit province, where over 60 schools had been reportedly burgled and vandalised, News24 previously reported.