The Teachers' Union of Ireland has called for the immediate reversal of a Government decision to suspend the payment of allowances to new teachers.
The decision reduces the pay of new entrants by up to several thousand euro.
The Association of Secondary Teachers Ireland has also strongly criticised the decision, which both unions say was taken unilaterally with no consultation.
The move affects allowances paid to teachers over and above their basic salary.
A teacher with an Honours Higher Diploma gets an additional €1,200 per year, for example, while an Honours Masters Degree attracts an extra €5,500.
There are payments for teachers who undertake supervision duties, while other allowances include one for island teachers or those who teach through Irish.
However, yesterday evening the Department of Education suspended all of these payments pending a review by the Department of Public Expenditure and Reform.
A spokesperson said that review was expected to be completed by the end of the month.
There has been a strong reaction from the two second-level teachers' unions.
The ASTI called it yet another disgraceful attack on vulnerable young teachers, while the TUI has called for an immediate reversal.
It accused the department of an outrageous betrayal of trust that shows contempt for agreed industrial relations procedures.