The ability of secondary school students to opt out of religious instruction, and religious ceremonies such as masses held during school time, has been strengthened by new regulations to be communicated to schools today.
The Department of Education will instruct State schools to offer alternative subject choices to all students who do not wish to study the subject.
It will tell them that parents must be made aware of the options available and must be asked to choose between religious instruction and the alternative.
The new regulations will affect around 160,000 secondary school students, which is almost half the entire secondary school population.
Until now, students who did not want to do religion in these schools were frequently required to remain physically in the classroom while the religion lesson was in progress.
In a circular sent to State run schools today, the Department of Education said the constitutional right to not attend religious instruction must be given effect through changed practices.
It said past practice of assuming that pupils are predominantly Catholic and arranging religious instruction accordingly is no longer appropriate.
It said a school must establish the wishes of parents - or students in the case of those over 18 - as part of its overall process of establishing subject choices generally.
The new regulations are effective immediately, however the Department of Education acknowledges that schools may need to wait until the next school year in order to introduce revised timetables.
All community and Education and Training Board or ETB (formerly VEC) schools are affected, but the new rules do not apply to religious-run schools.
In relation to making arrangements for students who may not wish to attend masses or other religious ceremonies held during school time, the department says best practice will involve providing parents with information about religious worship in the school, including its frequency, timing, duration and nature.
It says parents should be given the opportunity to advise the school of whether or not they want their child to take part.
Minister for Education Richard Bruton said it is a constitutional right for those who do not want to participate in religion, to be provided with an alternative, meaningful programme.
Speaking on RTÉ's Today with Sean O'Rourke, he said that Community and ETB schools will have to re-configure their timetables.
Mr Bruton said extra resources will not be offered because a new programme will not be required to meet pupils' needs.
He said that this is a statement of principle to the approach that needs to be taken. It reflects a changing need in Irish society, he said, and the admissions bill will require schools to set out how it will deal with students who want to opt out.
The Teachers' Union of Ireland said it has concerns over the resourcing of the programme, which it says will require additional teachers to provide the other subject options.
The Association of Secondary Teachers in Ireland has welcomed the new arrangements.
However, it said it will have resource implications for schools and as a result the ASTI will be raising this matter with the department "as a matter of urgency."
The General Secretary of the Teachers' Union of Ireland said the minister should not incentivise opting out of religion by suggesting that an alternative subject is available, as he said this was an expectation that schools cannot deliver.
Speaking on RTÉ's News at One, John MacGabhann said Mr Bruton "should not go beyond that and incentivise opt out by suggesting, falsely suggesting at the moment, that an alternative provision in terms of subjects can be made".
Meanwhile, April Duff, Legal Officer with Education Equality, said the move was very welcome and very positive and that at the moment, a student's right to opt out is not being respected in the majority of schools.
She said she did not believe it would be difficult to implement, but if additional resources were needed, they must be provided.
Ms Duff said the move would only affect around a third of students and needed to be widened to include all primary and secondary schools.
The General Secretary of Education Training Boards Ireland said providing an alternative parallel for religion will have resourcing implications, regardless of what Minister Bruton believes.
Michael Moriarty said it will be difficult to address, particularly when there are already teacher shortages in a number of subjects.