Correctional Services spokesman Manelisi Wolela has denied allegations that student leader Mcebo Dla.
The shortage of teachers in certain subjects in Mpumalanga has forced one teacher to teach more than one subject a day.
"Here you find one teacher teaching one subject in the morning, a different one during the day and another in the afternoon," said a teacher who spoke to Sowetan on condition of anonymity.
Authorities said the problem was due to the shortage of maths and science teachers. The schools in far-flung rural areas of the province are the hardest hit.
The affected schools include Gobolibi Secondary in Matimpule village, Malatse High in Lefiso and Sthembisile in Kuduspoort.
"We can't cope, especially in this new national curriculum," one of the teachers said.
Provincial education department spokesman Jasper Zwane admitted that there was a problem.
He said the department had employed a total of 32787 teachers but it was difficult to find maths and science teachers. "This has resulted in some teachers being forced to teach more than one subject in their schools," he said.