The National Union of Teachers (NUT) has passed a priority motion on pensions, which could see its members undertake strike action.
Christine Blower, general secretary of the union, said at its Harrogate conference this week that the ballot for industrial action has sent a "clear message" to the government that teachers will not tolerate their pensions being diminished.
"The support for this motion, together with the similar motion passed by ATL (Association of Teachers and Lecturers) conference, demonstrates the strength of feeling across the profession against the government's plans," she said.
Ms Blower added: "The government threatens teachers and all public sector workers with having to pay more for their pensions, work longer and get less in retirement."
The government intends to publish its finalised plans for teacher pensions in June and the NUT believes that the planned three per cent increase will actually represent a "significant pay cut" for teachers when the rising cost of living is factored in.