The Department of Education says reduced timetables for children should only be considered in exceptional circumstances.
Draft guidelines for schools will be discussed at the Oireachtas education committee today.
They say reduced timetables should only be considered in very limited and short-term circumstances, such as for medical reasons.
Schools must get parental consent, while the child should also be consulted.
Sinn Féin's education spokesman, Donnchadh Ó Laoghaire, says the system's currently being abused.