The archbishop criticised parents who deliberately opt out of diversification by sending their children to select schools and putting their education above the “common good”.

In an address to a National Association of Principals and Deputy Principals (NAPD) seminar on diversity in second-level schools yesterday, Dr Martin said wider educational patronage is desirable and welcome.

Catholic bishops are patron to 93% of the 3,260 primary schools and more than half of the country’s 740 second-level schools.

“The Catholic school will only be able to carry out its specific role if there are viable alternatives for parents who wish to send their children to schools inspired by other philosophies.

“The Government’s delay in providing such alternative models makes true choice difficult for those parents, but it also makes it more difficult for Catholic schools to do their work and maintain their identity,” he said.

In response to an increasingly diverse population, the Department of Education is piloting a new model of a community primary school in Dublin to accommodate children of all faiths or with no religious background. The first two will open in September.

The archbishop said schools must help foster a climate of knowledge about various religions in an increasingly pluralist Ireland but that there are limits to what a school can achieve.

He added that he would be unhappy if Catholic secondary schools were to become mainly elitist, or less open to diversity than others.

“I am unhappy when Catholic parents opt out of diversity and send their children to schools where there is less diversity, while I recognise that parents wish to get the best possible education for their children and have the right to choose the school they consider best,” he said.

Education Minister Mary Hanafin, whose department has been examining the enrolment policies and inclusiveness of schools, told the NAPD seminar that more than 17,000 of the country’s 330,000 second- level students claim a nationality other than Irish.

She has commissioned research on how increasing diversity of students affects school resources.

Her department will spend €120 million on English language resource teachers in schools this year.