INTO President Declan Kelleher has told delegates attending its annual congress that the Goverment will pay the price for cuts to education.
The INTO annual conference takes place in Letterkenny.
In a speech to delegates, Declan Kelleher criticised cuts in special needs classes in disadvantaged areas and in teachers' salaries.
Mr Kelleher said the government would pay the price when the Local and European elections are held in June.
He was given a standing ovation from hundreds of INTO delegates as he finished his speech.
The speech was a wide-ranging attack on Government policy.
Mr Kelleher referred to parental fundraising for schools and he called the cutting of special needs classes in disadvantaged areas the cruellest cut of all.
The outrage shown at last year's protests, he said, would be clearly articulated by teachers on 5 June, the day of European and local elections.
Referring to cuts of between 10% and 14% in teacher's salaries, Mr Kelleher said the Government would reap the reward for this too.
