The Peruvian government says the teachers' strike which has been taking place in the capital, Lima, since July 12 is illegal.
The announcement was made by the Regional Directorate of Education of Metropolitan Lima.
It also said the salaries of some 5000 teachers would be cut.
The directorate said the wage deductions were a direct result of public educational institutions refusing to carry out their work during the strike.
But negotiatons to try to find an end to the dispute are continuing.
"Teachers in the streets by the government's fault."
Previously, the Ministry of Education had reached an agreement with several regional leaders to increase the minimum wage for teachers to US$615 a month by December, less than their counterparts in neighboring Ecuador and Colombia.
The government had also agreed to complete a study in four months time, examining the strikers' demands for salaries to rise US$1233 by 2021.
The “indefinite strike” started on June 15 in Cusco, and was soon followed by other 12 regions across the country.
Some of the unions involved have been accused of having links with the Shining Path guerilla group, which they have rejected, arguing that such claims are part of a strategy designed to stigmatize and criminalize their members, and deny their political rights.