Archbishop Denis Hart asked that children at Catholic schools be given booklets opposing same-sex marriage.

The Archbishop of Melbourne wrote to Catholic primary and secondary schools to urge them to promote “the meaning of marriage”. He included a 15-page document, that children have been taking home to their parents.

Headteachers were asked to give parents a letter from Australian bishops entitled “Don’t Mess With Marriage”.

He wrote: “You might also consider asking them to send it to their Members of Parliament with a covering letter.”

Some headteachers have reportedly refused to pass the materials on.

Director of LGBT group Safe Schools Coalition, Roz Ward, said the material risked the well-being of LGBT Catholic students and urged headteachers not to hand out the material.

She told The Age: “At school it is particularly important that they can feel they can be themselves and valued for who they. In a situation where you feel that is not valued, everything else becomes more difficult.

“[It may be viewed as] a direct attack on their existence as gay Catholics.”

A political commentator in Australia said the country should not follow the lead of the Republic Ireland, who recently voted to introduce same-sex marriage, because: “these are people who can’t grow potatoes.

“They’ve got a mutant lawn weed as their national symbol and they can’t verbalise the difference between tree and the number three.”