Liberal Senator Cory Bernardi has come under fire with his recent controversial comment that legalising same sex marriage would only lead to calls for the legalisation of polygamous marriages as well.

The latest to express dismay over Mr. Bernardi's opinion is Tony Abott's gay sister, Christine Forster.

On Twitter, Ms. Forster did not hold back and said: "Cory Bernardi's comments in today's SMH are an affront to me, my partner and our relationship."

His latest comment was made ahead of a Senate debate that would tackle the bill proposed by Greens to recognise internationally sanctioned same-sex marriages.

Senator Bernardi, the dismissed personal parliamentary secretary of Tony Abott, was earlier quoted to have said: "I stand on the record and say, well I was right."

"I think there should be alarm ... if you're going to redefine a word to satisfy demands of a minority then you're going to face continuing demands in that space," Mr. Bernardi told Fairfax Media on Tuesday.

He particularly cited the petition raised by Polyamory Action Lobby which sought the parliament's move to legally acknowledge polygamous marriages as well.

He said that although it would sound such an extreme example, same-sex and polygamous marriages are actually linked together and that this was the radical agenda of the Greens party.

He admitted that he had to give up his position with Mr. Abott because his opinions had led to a "massive storm" that the Coalition did not deserve. He said he thought the "storm" was not justified.

Meanwhile, another person to express her distaste over Senator Bernardi's statement is Greens senator Sarah Hanson-Young. She said it seemed that the Liberal Senator did not learn from his experience last year.

"Linking the love that thousands of Australian couples share to bestiality is disgraceful," she told reporters in Canberra today. She said his statement would only make South Australians think twice about choosing Liberal in the next elections.

Also, Australian Marriage Equality spokesman Rodney Croome labelled Senator Bernardi's remarks as offensive.

"Not one country that has allowed same-sex marriage has moved to legitimise polygamy or bestiality - for the simply reason they're not linked, legally, socially or culturally," he said.