The row over a new system of appointing teachers, which led to ugly clashes with the police at the end of term, looks set to continue after the summer break.

At issue is the education ministry’s decision to make teachers sit examinations every two years for new appointments, instead of selecting them from a national register. A mixed system will apply over the next five years, with some appointments made from the register and others from successful exam candidates.

Teachers’ unions strongly opposed the reform, arguing that the exams denigrated the profession, and rendered their degrees useless. They called for a boycott.

Gerasimos Arsenis, the education secretary, was warned that violence was likely to occur if some teachers defied the union ban, as some exam centres were already occupied by demonstrating teachers.

But he refused to postpone or cancel the exams, relying instead on police protection for candidates.

In several centres, teachers entered peacefully, received the papers, refused to sit the exam, and left. In a few key places, unemployed teachers wanting to take the exam were guarded by police. Violence broke out when they were attacked by protesters. Police retaliated with truncheons, tear gas and water cannons. Nikos Tsoulias, president of the Teachers’ Federation, ended up in hospital.

In the aftermath of the battles, Mr Arsenis said he was satisfied by the number of candidates who took the exam. He praised the police for their handling of the situation, and he ruled out any possibility of a repeat of the exams affected by the disruptions.

The Teachers’ Federation is considering appealing to the supreme court to declare the exams null and void on the basis that the candidates were unable to compete on equal terms as a result of multiple disruptions.