Merit rises of £1,000 a year for up to 30,000 senior teachers face being frozen next year as school budgets are squeezed.
Leaders of the country's head teachers' organisations, the National Association of Head Teachers and the Secondary Heads Association, are warning they may block the rises.
The move will infuriate teachers' unions, which will claim thousands are being denied a rise to which they are entitled. Charles Clarke, the Secretary of State for Education, has asked the profession's pay review body to award the rises to only 30 per cent of the 30,000 eligible staff.
At present, around 90 per cent of teachers receive the rise, causing school salary costs to rocket and alarming ministers who are struggling to avoid a repeat of this year's budget cuts in schools which led to more than 1,000 teachers being declared redundant.
The difference in cost between 30 per cent and 90 per cent getting the rises is £20m - the equivalent of 600 full-time teaching jobs.
In a report to be published tomorrow, the review body is expected to reject Mr Clarke's suggestion and call for talks between ministers and head teachers to devise a better system for allocating the rises.
John Dunford, general secretary of the Secondary Heads Association, said: "The best way forward would be a freeze until a new system can be sorted out. We could always backdate the pay of those who became eligible."
When David Blunkett, the then Secretary of State for Education introduced the merit awards he billed them as an opportunity for teachers to stay in the classroom and still earn £40,000 a year.
Tomorrow's report is likely to propose an across-the-board pay rise of just over 2.5 per cent. The National Union of Teachers wants 10 per cent.
¿ A record 40,000 would-be teachers have applied for training courses in England this autumn - a 50 per cent increase on five years ago. Maths recruits are up by 16 per cent.Reuse content