Ballarat's bishop Garry Weatherill, who opposes the referendum, told the ABC that he supported "marriage equality".
Bishop Weatherill said: "The local position of this particular bishop is for marriage equality. The Bible teaches marriage is for man and woman, that is pretty clear and that is our standard position. But it is saying marriage is good for people and society, and I think whether or not we approve of same gender relationships, we want people to be in strong, monogamous and sustainable relationships that give harmony to their lives and to the community."
His comments come after Prime Minister Malcolm Turnbull this week introduced legislation into the Lower House for a plebiscite on same-sex marriage to be held on February 11.
The Labor opposition is expected to attempt to block the bill.
The bishop has spoken out against the plebiscite, arguing that Parliament should decide on such matters and that it is "almost inevitable" that hate speech will rise in the event of a national vote.
"It is the issue of respect that concerns me about the plebiscite. It is about the distress it could cause in the community, particularly among young, gay or sexually confused young people," he said. "The Government has quite sensibly tried to say there will be equal amounts of money for both sides of the argument, but who knows where other money will come from."