The teachers, under the banner of Nagar Nigam Shikshak Sangh (NNSS), also claimed that teaching was getting "affected" due to "non-filling" of teachers' positions at schools.
Several contractual teachers were hired in 2001 by the then unified Municipal Corporation of Delhi (MCD). NNSS General Secretary Ram Niwas Solanki said that NDMC and SDMC employees' contract was to be renewed this month.
MCD was trifurcated in 2012 into North Delhi Municipal Corporation (NDMC), South Delhi Municipal Corporation (SDMC) and East Delhi Municipal Corporation (EDMC).
"We have to see the student strength and other requirements at our schools. Only then can we take a decision.
"The final decision, of course, is taken by the Standing Committee," the official said on condition of anonymity.
"It is the discretion of the civic bodies whether or not to continue with their (contractual teachers') services," he said, adding that "only after recruiting full-time teachers will we look into the requirement for contractual employees".