The Catholic Church in Australia has launched a month of prayer and fasting to defeat a postal survey which asks whether the government should extend marriage rights to gay and lesbian couples.

Bishop Michael Kennedy of the Catholic diocese of Armidale recorded a video in support of the effort. In the 2-minute video, Kennedy asks for prayers for the nation's leaders. “We pray that they will uphold God's plan for marriage in our nation,” Kennedy said.

A group of Christian leaders opposed to same-sex marriage is backing the effort. Led by James Condon, a commissioner with the Salvation Army, Ps Peter Walker, an indigenous leader from the Uluru Bark Petition, and Warwick Marsh, a spokesman for the Canberra Declaration, a Christian document in support of marriage as a heterosexual union, the group is calling for the world to join in praying for a “miracle for marriage” in Australia.

“The polls are predicting a defeat for those who believe in the biblical definition of marriage,” the members said in a press release. “Australian Christians are asking for prayer from all over the world for a 'miracle for marriage' in Australia. The ballots must be posted back by the end of October. The Catholic Church has called for a month of 'Prayer and Fasting for Marriage and Families' through the month of October 2017.”

David Rowsome, a co-writer of the Canberra Declaration, said: “We as believers must approach these issues with great humility as marriage has been greatly damaged under our watch. Collectively, we as nation must ask God for forgiveness for our failure and truly repent. At the same time, we need to pray for God's grace to be shown to marriages and families in distress.”

Results from the postal survey are expected to be released November 15.