The changes would make civil partnerships practically indistinguishable from traditional weddings, delighting equality campaigners but leading to fierce opposition from mainstream Christian leaders who believe marriage can only take place between a man and a woman.

Church of England sources warned that the Government could not make such dramatic changes merely by issuing regulations or guidance, as the current Civil Partnership Act prohibits the use of religious services during the registrations.

A spokesman made it clear that senior figures in the established faith will resist any moves to legalise gay marriage, saying: "The Church of England is not proposing to open its churches for civil partnership registrations. Any comment we might wish to make on the principles of these apparent proposals would be made through the formal consultation process."

The Rt Rev Michael Langrish, the Bishop of Exeter, added in a personal statement: "As some of us warned at the time, the amendment to the Equality Bill has opened an area of unhelpful doubt and confusion. The Church of England will not be allowing use of any of its buildings for civil partnership registrations, but will no doubt wish to respond if and when HMG decides to consult."

Since 2005, same-sex couples in Britain have been allowed to take part in civil partnership ceremonies. These give them similar legal rights to married spouses, but the law required the events to take place in register offices or approved venues such as hotels and stately homes. The ceremony itself has had to be secular, with no hymns or Bible readings, in order to preserve the historic definition of religious marriage as the union of a man and a woman.

When Labour's flagship Equality Act was being debated earlier this year, an amendment was added in the Lords that permitted civil partnerships to take place in places of worship if the relevant religious group permitted it. Quakers, Unitarians and the Liberal Judaism movement will ask to be allowed to host the ceremonies but the Church of England will resist it, despite the wishes of some liberal clerics, as will the Roman Catholic Church in England and Wales.

No changes to the nature of the ceremonies were proposed in the Lords and in a Parliamentary written answer last month, it was made clear that they must be "entirely secular in nature" and cannot contain "any religious language".

But in a Parliamentary written answer provided on Wednesday to Chris Bryant, the former Labour minister who posed in his underpants on a dating website called Gaydar, it emerged that the Coalition is considering moving further towards legalising full gay marriage as it draws up the regulations on how civil partnerships can be held in places of worship.

Lynne Featherstone, the Liberal Democrat equalities minister, said: "An amendment made in the House of Lords to the Equality Act 2010 removed the express prohibition on civil partnership registrations taking place on religious premises.

"In response to this amendment, the Government committed to talking to those with a key interest in the issue of civil partnerships on what the next stage should be for civil partnerships.

"This will include consideration of whether civil partnerships should be allowed to include religious readings, music and symbols.

"This commitment was made through the document, Working for Lesbian, Gay, Bisexual and Transgender Equality, published on 16 June 2010."

During the election campaign, the Conservatives were the only main party to suggest that they would allow gay marriage.

Their Contract for Equalities stated: "We will consider the case for changing the law to allow civil partnerships to be called and classified as marriage."

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