The organisation accused the Government of ignoring widespread public opinion in favour of the current definition as a union between a man and a woman.
The consultation paper states: "This consultation is about how we best remove the ban on same-sex couples having a civil marriage, not on whether this should or should not happen.
"However, we are aware that there are a number of disparate views on this subject and would like to understand the views of all of those with an interest in this issue."
The Evangelical Alliance said that the consultation paper was a "blatant acknowledgement" by the Government that it is "only going through the motions" of a consultation.
It questioned why the Government is pushing the changes through despite evidence of strong opposition.
A recent survey by Catholic Voices found that 70% of the population believe the definition of marriage should remain as a union between a man and a woman.
A petition launched three weeks ago by the Coalition For Marriage in opposition to the change has been signed by more than 215,000 people.
The Evangelical Alliance said that the Government appeared to be intent on ignoring public opinion and seeking to force through a redefinition of marriage as a "done deal".
Dr Dave Landrum,director of advocacy for the Evangelical Alliance said: "When is a consultation not a consultation? The Government's attempt to ignore public opinion about marriage has been a feature of their proposals from the outset.
"With 70 per cent of the population against marriage being redefined, it seems that politics is yet again falling short of what people want and is bringing the entire democratic process into disrepute.
"Changes to marriage are wanted only by a small, political elite and a few activist groups. It is clear that there is no public appetite for it so politicians should keep their hands off marriage and listen to what the country wants."
A poll of Scots has found similar resistance north of the border, where the Scottish Government has also proposed legalising gay marriage.
In a survey of more than 1,000 people by Opinion Research Business, 85% agreed that it was "possible to be tolerant of the rights of others and protective of traditional marriage at the same time.
The survey, conducted for the campaign group Scotland for Marriage, also revealed that 71% do not believe "defending traditional marriage is discriminating against gays and lesbians".
More than two-thirds (69%) endorsed the view that "the ideal situation for a child is to be raised by a married mother and a father".
A spokesman for Scotland for Marriage campaign said the findings were a sign that there was no majority support for gay marriage.
"These results demonstrate clearly that Scotland supports marriage with an overwhelming majority believing that wherever possible every child should be raised by a mother and a father," he said.
"There is clearly no support whatsoever for a society which creates in law a situation which deliberately deprives a child of a mother or a father.
"I hope that the Scottish Government will consider these findings very carefully and accept that objections to their proposals are not primarily religious but exist widely across society among people of all faiths and none."