A father has gathered almost 18,000 signatures on a petition to change an amendment which allows schools to grant preference for places to baptised Catholic children.
Paddy Monahan, who works a barrister, said that he started the campaign when he realised the law meant his son could be turned away from schools because he is not baptised.
The petition for equal school access and the removal of religious barriers to taxpayer-funded schools is to be handed into Leinster House tomorrow afternoon.
Mr Monahan said that his son is only eight months old, but he is thinking ahead.
"This law puts ridiculous pressure on parents, essentially to get their children baptised in order to be in the top category," he said.
"About 97% of schools - what they have is enrolment criteria and in the top category in all those schools it's whether or not your child is baptised - and then the second category will be 'is your child baptised from outside the area'.
"Then further down the list, my child at the moment he's 'Other' - he's in the category marked as 'Other'."