"This is a great response from teachers on the first of four striek days," Fenprof's secretary general told reporters.

"If the Government has not heard the teachers in the negotiation it will hear them on the streets," Mário Nogueira said in Lisbon, in an assessment of the first morning of strikes .

On Monday, teachers' unions and the Ministry of Education failed to reach agreement on how years of work carried out during a period of wage freezes should be counted .

The minitry is offering to count two years and ten months of service for the teachers, while the teachers say they will not give up on the entire period of nine years and four months being counted towards their career progression, salaries and future pensions.

As they failed to reach an agreement, the teachers began the strike that had previously scheduled for between Tuesday and Friday.

The strike includes schools in the districts of Lisbon, Setúbal and Santarém and in the autonomous region of Madeira, on Wednesday it will include schools in the south region (Évora, Portalegre, Beja and Faro), on Thursday those in the central region (Coimbra, Viseu, Aveiro, Leiria, Guarda and Castelo Branco) and, on Friday, it is the turn of the north (Porto, Braga, Viana do Castelo, Vila Real and Bragança) and the autonomous region of the Azores.