Under the new regulations teachers must be appraised by a senior member of staff and agree a set of objectives for the coming year by February 28.
But the National Union of Teachers argues that many schools, particularly those struggling to cope with shortages, must be given more time.
Ministers have already put back their performance-management deadline for headteachers to be appraised by their governors. All 24,000 school boards in England now have until April 6 to meet with their heads, not the end of December as originally planned.
But the Department for Education and Employment is adamant that the timing for teachers willnot be changed. In a letter to the union the DFEE said it "could cause confusion and disrupt the process more than it helps".
The union has also criticised regulations which it claims will allow any governor access to teachers' appraisal documentation. The regulations require heads to make appraisal forms available to any governor responsible for "advising or taking decisions" about the promotion or pay of a teacher. The union fears that any governor could argue that they wanted to give advice and "interfere" with the appointments process, regardless of whether they were actually responsible for making the decision.
The DFEE believes the regulations are clear and that only governors who are explicitly responsible for the appointment will be able to see the appraisal documents.