Unions representing secondary school teachers have ordered their members to escalate industrial action against cutbacks.
A new directive says teachers should not do the work of those at middle management level who are not replaced once they retire.
That covers assistant principals and special-duties teachers, hundreds of whom have already retired since September, and have not been replaced.
It is thought the new measure, which takes effect from March 8, will affect areas like exam timetables and organisation, Transition Year co-ordination and extra-curricular activities.
A spokesperson for Education Minister Batt O'Keefe said the Minister regretted the unions' decision to take this action "because it will make it more difficult for schools to manage in these difficult times".
The spokesperson reiterated that the moratorium on the filling of vacant promotion posts is being applied across the public service generally, and that schools are still recruiting new teachers to fill vacancies with only promotion posts are being restricted.
"These extraordinarily difficult times need us all to pull together," a statement said. "We must acknowledge that teachers have and retain a strong commitment to their pupils."
"The Government's responsibilities to these same pupils required that difficult decisions be taken to secure our longer-term wellbeing."
Meanwhile union leaders will address their members at a major meeting of public servants in Galway this evening
The unions say they have a viable alternative to pay cuts which can provide savings within the public service as well as improving productivity.