Half of young teachers work part-time
One-in-two second-level teachers under the age of 30 have only part-time jobs, according to the Teachers Union of Ireland (TUI).
Many of them are struggling to get by and meet even the most modest financial commitments, said TUI president Gerry Quinn.
He said where once teachers, and lecturers in institutes of technology, applied for full-time, permanent positions, for several years now they have been applying for fragments of jobs with no guarantee of being retained from year to year.
To make matters worse, teachers who entered the profession from 2011 are on a severely cut salary scale, he said.
The TUI president said casualisation created instability for everybody in the school, not least students who were often taught by a succession of teachers in a given subject area over the course of the Junior or Leaving Certificate cycles.
"In terms of consistency of provision, this is undesirable, unacceptable and damaging," he said.
Casualisation of the second-level teaching profession has been recognised as a major problem and some improvements in employment terms will be introduced in September, following a report from an expert group.
Mr Quinn said that although these measures were very welcome and went some distance in the right direction, they would not fully address the crisis.
The union estimates that, overall, about 30pc of second-level teachers are employed on a part-time basis, rising to 50pc among the under-30s.
The TUI is now calling for any new teaching hours in schools to be given to existing part-time staff in the first instance, rather than recruiting, "and in some cases exploiting, additional part-time staff".
Mr Quinn said this mechanism should be mandatory.