Risking accusations it was undermining marriage, the church said cohabiting couples with children should be granted significant legal protection if they split up.
The church appeared to contradict the views of Archbishop of Canterbury Rowan Williams, The Telegraph of London reported Wednesday.
In June, when the church was considering recommendations from its Law Commission, Williams said marriage had "suffered a long process of erosion" and the commission's proposals would further add to "a prevailing social muddle."
In supporting the proposals, the church also argued legal rights should be extended to unmarried couples without children if one of the ex-partners was at risk of suffering a substantial injustice when they separated.
The church said it sought to uphold the ideal of marriage but said there was a strong biblical precedent for protecting the vulnerable.