CANBERRA, Australia (CNS) — Redefining marriage will be a “serious injustice” with far-reaching consequences for all, Australia’s Catholic bishops warned as the push for legalizing same-sex marriage in the country appeared to be reaching a crescendo.

On May 28, the bishops released a pastoral letter on same-sex marriage, which was fast-tracked for distribution given the impending introduction of draft legislation on same-sex marriage in the Australian Parliament.

Two days earlier, Opposition Leader Bill Shorten announced his plan to redefine marriage. Debate was expected to begin in the House of Representatives June 1, and the legislation could be passed as early as August.

The bishops’ letter was distributed to all dioceses in Australia, which in turn will distribute the letter to parishes, schools and agencies.

It argues that it is “gravely unjust” to legitimize the false assertion that there is nothing distinctive about a man and a woman, a father or a mother; to ignore the importance for children of having a mother and a father, committed to them and to each other for the long haul; and to destabilize marriage further at a time when it is already under considerable pressure.

“If we are right in this assertion and if the civil law ceases to define marriage as traditionally understood, it will be a serious injustice and undermine that common good for which the civil law exists,” the letter said.

“Marriage,” it said, “is the covenant of a man and a woman to live as husband and wife, exclusively and for life, and open to the procreation of children.”

If marriage is redefined, “All marriages would come to be defined by intensity of emotion rather than a union founded on sexual complementarity and potential fertility,” the bishops said. “Freedom of conscience, belief and worship will be curtailed in important ways.”

The bishops called upon people to contact their legislators and to “redouble their support for the institution of marriage in our community and for the laws and culture that sustain it.”