Mr Shorten stated his opinion on the issue at the Australian Christian Lobby National Conference in Canberra yesterday.

He said as a Christian, he believed in same-sex marriage and that it should be legalised in Australia.

"When I hear people invoking scriptures to attack blended families like mine I cannot stay silent - I do not agree," Mr Shorten said.

"These prejudices do not reflect the Christian values that I believe in."

Tasmanian Gay and Lesbian Rights Group spokesman Rodney Croome said the speech shows the opposition leader's strength of character.

"We live in a secular country and we should be governed by secular laws not biblical values," Mr Croome said.

"When historians come to write the history of this issue, they will see this as a turning point in the debate.

"I respect the views of people of faith, and faith-communities will not have to marry same-sex couples if they don't want to, but at the same time the Bible is not the basis for civil law."

Rainbow Communities Tasmania chairwoman Deidre Murray said she felt the speech was a heartfelt account of what a lot of Australians felt.

"I think it's important that people understand that people of all walks of life are interested in seeing equality for everybody," Ms Murray said.

"At the end of the day, we're all people and we should all be free to really live, love and raise our families in equality.

"We've got to learn to be more understanding of everybody. It's about everybody's rights."