Teachers’ unions have warned that restricting career breaks will make the profession less attractive.
Amid staff shortage issues, Teachers’ Union of Ireland (TUI) president Joanne Irwin said that limiting the option would make it more difficult to retain secondary teachers.
Some 2,264 teachers are on career breaks of up to five years and advisories are being issued that career breaks can only be granted if a vacancy can be filled.
But Ms Irwin said: "This is yet another ill-advised ’sticking plaster’ approach that ignores the urgent need to remedy a much more serious problem.
"Restrictions on career breaks seriously risk exacerbating the crisis both in the recruitment and retention of teachers."
The issue of career breaks has emerged as primary schools report difficulties in recruiting substitutes to cover temporary absences and secondary schools report difficulties in recruiting teachers for certain subjects.
Recent figures showed the number of people applying to be teachers has dropped by 62% in the past five years.
But there is also the issue of a two-tier pay system for teachers who qualified since 2011 and large numbers of newly qualified teachers going abroad to work.
Education Minister Richard Bruton said: "While a career break is an important option, it is a discretionary scheme which requires the approval of the school.
"It has the effect of replacing a permanent position in a school with a temporary one, where a school is left in a position where it can only offer a one-year temporary contract to prospective candidates.
"This is not appealing to many teachers given the large number of permanent jobs which are available."
Ms Irwin said the main issue was equal pay.
"Pay inequality is the problem, not career breaks," the TUI chief said.
"Yet the minister stubbornly and foolishly continues to focus on the symptom rather than the disease."
INTO general secretary Sheila Nunan said there was no evidence that schools had difficulties in filling vacancies caused by teachers on career breaks and that it created employment for new entrants.
"Stopping breaks would close off those employment opportunities and lead to new entrants being unemployed," Ms Nunan said.
The INTO leader said the minister’s proposals would result in a different cohort of teachers going abroad to seek work.
ASTI deputy general secretary Diarmaid de Paor said maternity leave was one of the reasons principals were trying to fill vacancies.
"It is good for all of society to support these new families through maternity leave, and also through career breaks in so far as possible," Mr de Paor said.
He added the option of a career break was what helped make teaching an attractive job for many and urged schools to do their best to continue to grant the leave.