The union representing secondary school teachers (OLME) said on Friday that there is a shortage of some 2,000 educators at junior and senior high schools.
OLME said that the Education Ministry has asked for some classes to be merged so teachers can be freed up to cover for shortages elsewhere.
OLME said that as a result of a lack of educators, some lessons are not being taught at certain schools.
OLME members are due to protest in front of the Education Ministry on Tuesday at 12.30 p.m. In order to take part in the protest, teachers will hold a work stoppage from 11 a.m. to 2 p.m. and from 2 to 5 p.m., according to whether they work morning or afternoon shifts.