Archbishop Peter Smith of Southwark released a statement after Tuesday's 400-175 vote in the House of Commons in favor of same-sex "marriage."
The legislation is now set to come under more detailed parliamentary scrutiny.
"The Catholic Church continues to support marriage understood by society for centuries as the significant and unique lifelong commitment between a man and a woman for their mutual well-being and open to the procreation and education of children," Archbishop Smith said in a statement.
The prelate affirmed the Church's opposition to the bill, adding that "despite claims by supporters of the Bill that the central issue is one of equality, the Bill actually seeks to re-define marriage and will have consequences for society at large."
"It became clear during today's debate in the House of Commons that the government has not thought through a number of profound problems in the Bill raised by members of Parliament during the debate," the archbishop warned. "It will be extremely important that the many concerns we and others have expressed will be fully and carefully considered during the next stages of the Bill's passage through Parliament."
According to the Catholic Herald, Bishop Philip Egan of Portsmouth spoke of the far-reaching consequences of the legislation.
"Just as the Church has been forced to abandon its adoption services, so too Catholics who work in the medical profession and in social services are going to find themselves under intolerable moral pressures," the bishop said in a statement. "These pressures will also arguably be felt throughout our Catholic schools, by teachers, staff and parents."
Catholic adoption agencies in Britain have been closing since 2008, when the law was changed to force them to place children with same-sex couples.