Minister for Education Richard Bruton has signed an order to outlaw the use of religion as a criteria for primary school admissions in almost all cases.
From today no Catholic primary school will be able to give preferential treatment to Catholic children when it comes to school admissions.
Other minority religion schools will however be allowed to continue to discriminate in favour of children of their own faith.
The commencement order to be signed by Mr Bruton will bring a number of sections of the Education (Admissions to Schools) Act into immediate operation.
They include a ban on the use of admission fees to secure school places in schools that are not fee paying.
They will also give powers to the minister to require schools to co-operate in relation to admissions, where required.
From December, the minister will also have power to compel a school to open a special class for children with disabilities, where deemed necessary.
Mr Bruton said that the order would ensure greater fairness in school admissions.
He said that while recognising the right of all schools to have their distinctive ethos, the removal of religion as a criteria for admission to school sought to be fair to all parents, including non-religious families, that would now find that in virtually all publicly-funded primary schools they would be treated the same as all other families in school admissions.
The minister said the provisions being enacted today would create greater confidence for parents that the admission criteria laid down by schools and the procedures used by them were visible, legitimate, reasonable and fair."
Speaking on RTÉ's Today with Sean O'Rourke, Mr Bruton said the changes would remove religion as a factor in admission in 19 out of every 20 schools.
He said schools could continue to enforce some of their own admission policies, such as catchment area and siblings criteria.
In addition, he said that where a child can show they use Irish regularly outside of school, a gaelscoil can give priority to that child.
Mr Bruton said there are school places for everyone but some schools are over subscribed and religion should not be used as a criteria where a child, from outside the area, might be given priority over a child who lives close to the school.
The Irish National Teachers’ Organisation has criticised the minister’s decision to commence provisions of the Education (Admissions to Schools) Act.
The union said the move has been taken without any consideration of the chaos it will cause in schools in the absence of specific guidance on implementation.
The INTO said it not opposed to the policy changes contained in the Act itself, but is concerned by the lack of guidance.
It said the measures will require the immediate adoption of new admissions policies at a time when school leaders are already under considerable pressure.