The Ayios Panteleimonas primary school in Limassol, which closed last week after a Covid cluster was discovered, reopened on Monday.
Limassol school board president Dinos Ellinas told CyBC that out of the 350 pupils at the school, 125 have had to stay at home as they are either active cases or contacts of cases.
The school closed from Tuesday to Friday last week after 35 cases of coronavirus were detected among pupils, staff and teachers.
Ellinas said that contact tracing showed some pupils were being sent to school with coronavirus symptoms, adding that parents have now been instructed not to send their children to school if they show any kind of symptoms.
The school will also send pupils showing symptoms home, he said.
In addition, he said that a mobile testing unit was at the school on Monday where children who had the consent of their parents, about 95 per cent of those who returned to school, were tested before going into the building.