Hove MP Mike Weatherley says churches should agree to conduct gay marriage ceremonies or lose the right to host weddings at all.
The Conservative backbencher has written to Prime Minister David Cameron to urge him to support the proposal.
Mr Weatherley believes that it would encourage gay marriages – or civil partnerships – to be treated more equally.
A number of gay couples would like to marry in church but until recently this was not permitted by law.
Mr Weatherley’s letter is likely to provoke resistance from many in the Church of England and the Roman Catholic Church.
It is unlikely to win support from key figures among the significant minority of Jews who live in Mr Weatherley’s constituency.
And Muslim leaders are also expected to oppose the idea.
Crucially, leading gay rights campaigners such as Peter Tatchell cautioned earlier this year against forcing religious leaders to conduct gay marriages.
He welcomed a recent change in the law brought in by the Equality Act permitting churches to marry gay couples.
But he said: “Permitting faith organisations to make their own decision on whether to conduct same-sex civil partnerships is the democratic and decent thing to do.
“The current law prevents them from doing so, even if they want to.
“No religious institution will be forced to perform civil partnerships if they do not wish to do so.”
When the recent reforms were discussed in the House of Lords, the recently retired Bishop of Chichester, the Right Reverend John Hind, whose diocese includes Brighton and Hove, spoke out against them.
Civil partnerships were brought in six years ago to give gay couples equal rights in law with heterosexual married couples.
But places of worship were not permitted to conduct civil partnership ceremonies by law until the Equality Act became law this year.
Brighton and Hove City Council conducts more civil partnership ceremonies than just about anywhere else in the country.
And the city has a high proportion of same-sex couples compared to other towns and cities, some of who are active in the local Conservative Party.
Mr Weatherley, who attended Brighton Pride last month, believes further reform of the law to force religious leaders to marry gay couples is the only way to bring about greater equality.
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