Performance-related pay for teachers will be brought a step nearer with an announcement by the government of a £22m training package for appraisals.

The extra funds, announced by the Education Minister, Charles Clarke, will provide training for headteachers in the appraisal system which will determine which teachers should be rewarded with a performance-related pay rise.

The biggest teachers' unions have threatened industrial to stop performance pay, arguing that it will be unfair and fails to tackle the underlying problem of inadequate pay.

But the government has insisted that it will press ahead with the linking of pay to teachers' levels of achievement, demanding that a £1bn investment in teachers' pay should produce a measurable improvement in teaching standards.

The funding for training, announced at the annual conference of the Professional Association of Teachers, will begin the process of preparing headteachers to evaluate their staff for merit pay.

"The government is confident it can give good teachers the rewards they deserve through a system that is fair, non-bureaucratic and effective. It is crucial that teachers have the skills and confidence to operate the new system of performance-related pay effectively," said Mr Clarke.

Under the government's proposals, teachers can apply to their headteachers for an appraisal which will judge whether they are of sufficient ability to cross a performance "threshold". If headteachers believe that teachers meet the required standard they will be eligible for a pay rise of up to £2,000.

The extra money for appraisal training will help to allay concerns that headteachers will not be adequately prepared to carry out the appraisal system - which will be at the centre of the government's efforts to introduce performance pay.