Five teachers have been slapped with show-cause letters for criticising the government in an excessive manner, said Education Minister Mahdzir Khalid.

In a Facebook posting, he said the five had shared the stage with the opposition.

“They will be called in to hear recordings of their speeches and be advised on following the subsequent process by the ministry's disciplinary department.

“I am not being too harsh, taking the approach of advising them for now,” he said.

Meanwhile, Mahdzir told the New Straits Times that one of the five teachers held a senior position in an opposition party.

The minister also said the government had no qualms with teachers offering constructive criticism, but they must use the proper channels to do so.

Yesterday, Mahdzir advised teachers actively promoting the opposition or discrediting the government to resign from the civil service.

He said all civil servants should realise that they are bound by the rules established in the general orders and criticising to the point of defaming was not right.

"If he or she is still a teacher and then climbs the stage to slam the government. Give lectures, and then add defamatory elements. I would like to remind him or her that it would be better to leave the profession.

"If he or she does this while being in the civil service... I do not feel it's healthy. I am not saying we are closing the doors of democracy but government servants are subject to the (terms of) civil service, there are circulars and general orders," he said.