"It is clear that changing the definition of marriage is not something that defined the way Australians voted despite Labor's high-profile campaigning on it and strong support for it in the media," ACL Managing Director Lyle Shelton said.
"Australia has an opportunity now to move on from this debate but if same-sex marriage activists persist in the new Parliament, it should go back to the people again for the ultimate conscience vote in a referendum," Mr Shelton said.
"Mr Rudd's bullying of a Christian pastor on Q&A in the final week of the campaign made Australians feel uncomfortable with the consequences for freedom of speech and freedom of belief should the law on marriage be changed," Mr Shelton said.
"It should not be up to politicians to decide to normalise this sort of treatment of fellow Australians who will always believe that marriage is between a man and a woman."
Mr Shelton said reforms in 2008 meant there was no discrimination against same-sex couples under Australian law and it was unnecessary to divide people in the way Mr Rudd did by changing the definition of marriage.
Despite the Greens championing of same-sex marriage, they had suffered a swing against them while a pro traditional marriage political party, Family First, looks to have picked up a Senate seat in South Australia.
Mr Shelton hoped Labor would realise the error of following Greens' social policy and of having changed its party platform on marriage at its 2011 National Conference.
"There is an opportunity now for Labor to further distance itself from the Greens and move back to the sensible centre on social policy as part of its rebuilding process."