Speaking in the Senate on Wednesday, she questioned why same-sex couples wanted the right to marry.

‘‘I doubt that most people who are pushing these amendments are overly religious or even intend on staying in a monogamous relationship, which begs the question: why do they want to get married?’’ Sen Fierravanti-Wells  said.

Like South Australian senator Cory Bernardi, who on Wednesday resigned after linking same-sex marriage to bestiality and polygamy, Sen Fierravanti-Wells said allowing same-sex couples to marry paved the way for marriages with multiple husbands or wives.

‘‘Most Australians would find these concepts repugnant, abhorrent and destructive to our social fabric,’’ she said.

‘‘But this is where we are heading.’’

Read the Senator's full speech here

The comments followed the defeat of Throsby MP Stephen Jones’s same-sex marriage bill on Wednesday, a result Sen Fierravanti-Wells described as a victory for ‘‘the silent majority’’.

‘‘The chattering classes do not want to concede that, by amending the Marriage Act, they are in fact denying the rights of the silent majority who want to uphold the sanctity and true meaning of marriage,’’ she said.

She said marriage was traditionally a religious ceremony and allowing marriage equality for same-sex couples could open ‘‘the backdoor to attacks on religious freedoms’’ by forcing churches to act outside their religious teachings.

‘‘It is a religious act that glorifies the significant union between a man and a woman,’’ she said.

‘‘An important part of the marriage journey is the public vows that a man and a woman make to each other before their God which commits them to each other for the rest of their natural lives.

 ‘‘This is not about equality; it is about the tearing down of our social fabric,’’ she said.

Sen Fierravanti-Wells said she had received thousands of messages of support.