Search and seizures operations were implemented at the gate of Excelsior Secondary School after a gun was found in a toilet cistern, the Western Cape Department of Education has confirmed.

The WCED on Thursday denied allegations that a shooting incident had occurred at the Belhar school last week, but confirmed that a firearm had been retrieved from the bathroom that day.

ANC activist Colin Arendse wrote an open letter to Education MEC Debbie Schafer, accusing the school management and department of covering up an alleged shooting inside a classroom involving a Grade 10 pupil last Friday.

Department spokesperson Bronagh Hammond, however, denied this.

"A device of some sort was detonated in a classroom while teaching and learning [were] taking place. SAPS were immediately called in and the school contacted the Safe School Call Centre immediately," she said.

All relevant procedures were followed, Hammond insisted.

She confirmed that the gun had been found in the toilet that same day.

"The weapon was then handed over to the principal, who handed it over the police, as per procedure. There is no evidence that the two - the detonation in the classroom and the gun - [are] related."

Hammond said department officials addressed pupils on Monday and met to determine a strategy together with the Department of Community Safety and City of Cape Town's law enforcement to address any potential safety risks.

It was decided that additional security, in terms of access control, would be provided by the community safety department, security risk assessments would be conducted, search and seizures would take place at the school gate, police would do random patrols, and the perimeter fence would be guarded.

Western Cape police spokesperson Sergeant Noloyiso Rwexana confirmed that they were investigating after a Norinco pistol was found abandoned at the school.

No one has been arrested.