Thousands of headteachers could miss out on pay rises this autumn because their governors have yet to fill out the relevant paperwork.
More than 3,000 schools have not yet booked an external adviser to help them appraise their heads, whose pay increases depend on them demonstrating improved performance against targets.
So far, nearly 12,000 of all maintained schools have been visited by one of the 2,000 advisers available.
Around 19,400 governing bodies have sent in adviser booking forms, and 18,200 have had responses from Cambridge Education Associates, the Department for Education and Employment contractor.
But 3,200 have yet to start the process. The deadline for completing headteacher appraisals has already been extended, from the end of last year to April 6.
Members of the National Association of Head Teachers have been advised to agree performance objectves with governors and present them to the external adviser when he or she calls. David Hart, general secretary, said:
"I don't want anyone to have an excuse for refusing to award heads a performance-related increment because nothing has been done until the external adviser arrives."
John Dunford, general secretary of the Secondary Heads' Association, added:
"Governing bodies should be moving on this if heads are to be eligible for increments related to targets and performance."
Governor organisations complained of administrative delays and misunderstandings in booking advisers. Jane Phillips, vice-chairwoman of the National Association of Governors and Managers, said they may have led some governors to give their head's appraisal "a lower priority than they might otherwise have done".
A spokeswoman for CEA insisted the company was on target to get all 22,600 adviser visits completed in time to meet the April 6 deadline.