Details of a new bill to abolish the so-called "baptism barrier" in schools will be announced today.
The Solidarity party's Equal Participation in Schools Bill would ensure that schools are not able to discriminate in admitting children on the grounds of religion, and would make the curriculum more inclusive.
The baptism barrier has been labelled a form of "apartheid" by those trying to change school admission laws.
Ruth Coppinger claims the Government's current consultation process is "ridiculous" as it allows religious orders retain control.
She said there were fewer people declaring themselves Catholic, and religious in general.
"All children should be treated equally. Schools should not be for faith formation; they should be for education," she said
"Taxpayers fund these schools and they should not be allowed to discriminate on the basis of religion.
"Even people who are practicing Catholics believe this should change."