Estelle Morris has ruled out teachers' demands that they spend a maximum of 22.5 hours a week in the classroom.
The decision, revealed in a letter to the chairman of the teachers' pay review body obtained by The Independent, will increase the prospect of national industrial action in schools. It further stokes the row between the Government and the three TUC-affiliated unions which begin their Easter conferences next week.
The Secretary of State for Education and Skills said she believed some of the demands made by unions and backed by their local education authority employers were "wrong and unworkable".
The unions failed to "explain why" they wanted a limit on classroom hours – the teachers' unions are seeking a maximum 22.5 hours a week, while headteachers want it capped at 21 hours for their staff.
Ms Morris said in her letter to Tony Vineall, the chairman of the review body: "All the evidence from teachers about workload issues makes clear their frustration at being diverted to routine clerical and administrative tasks, not at the amount of teaching they do."
She also repeated Labour's election pledge to employ at least 20,000 more classroom assistants.Reuse content