Circular 31/2011 details teacher registration and qualification requirements for appointment as a teacher in the primary and post primary sector.
Schools are required to prioritise registered teachers over unregistered persons, appropriately qualified teachers over teachers qualified in another sector and unemployed teachers over those in receipt of a pension. It may be the case that appropriately qualified and registered teachers who are not in receipt of a pension are simply unavailable either due to the notice period involved or due to geographical or role specific needs.
Schools are required to keep a list of appropriately qualified registered teachers who are available for substitute work at short notice. I would encourage unemployed teachers to ensure that they are registered with their local school / VEC for this purpose.