Archbishop Barry Morgan spoke at a meeting of church officials in Llandudno, The Independent reported.
Prime Minister David Cameron has proposed legalizing gay marriage in England and Wales. Rowan Williams, the archbishop of Canterbury, who was Morgan's predecessor in Wales, and most other senior church leaders have opposed it.
"If the legislation to allow civil marriage is passed, I cannot see how we as a church, will be able to ignore the legality of the status of such partnerships and we ought not to want to do so," Morgan said.
Morgan said he has heard from many homosexuals that they feel unwelcome in the Anglican church in Britain.
He had a question for the church: "The real question is, how do we hold together faithfulness to scripture and tradition with the wider New Testament call to love our neighbor? If the moral aim of the gospel is to encourage love of neighbors, how can that happen when people are made to feel unwanted, unloved, and sinful? How is the gospel good news for homosexuals?"