The same-sex proposals outlined by Conservative minister Maria Miller were met with entrenched opposition from the Tory backbenchers behind her.
Martin Vickers told her it was a "major social change that many of those we represent find unacceptable."
He said the measure should be allowed to "evolve rather than be pushed through".
North Thanet MP Sir Roger Gale said the letters he had received from his constituents suggested 98 per cent were against the plan.
Sir Roger told MPs he chaired the committee hearings on the legislation which enabled civil partnerships, and said assurances were then given that it would not lead to same-sex marriages.
Mrs Miller told him there were "important differences of perception" between civil partnerships and marriage.
Same-sex marriage will remain illegal in the Church of England, as the Government unveiled its plans to extend marriage to gay couples.
David Cameron is facing a backlash from Tory MPs and religious groups over allowing gay weddings in churches.