Tasmania's upper house, the Legislative Council, has passed a motion supporting same-sex marriage.
In 2012 a similar motion failed in the small and traditionally conservative upper house.
The bill was advanced by independent MLC Tony Mulder.
"Why do we have to treat this most personal of issues as if it was a threat to society? Or a threat to our way of life?" he said.
The motion of support will have no practical legal effect, in 2013 the High Court ruled that states do not have the constitutional power to over-rule federal laws blocking same-sex marriage.
The motion passed eight votes to five. Labor MLCs Craig Farrell and Josh Willie supported the bill, along with the Liberal Party's Vanessa Goodwin. Independents Kerry Finch, Ruth Forrest, Mike Gaffney and Rob Valentine were also supporters.
Independents Robert Armstrong, Ivan Dean, Greg Hall and Tania Rattray voted against the motion, along with Liberal Party MLC Leonie Hiscutt.
Australian Marriage Equality welcomed the vote, with a pointed comment in reference to the government's proposed national plebiscite on same-sex marriage.
“This result shows how Governments around the nation can achieve marriage equality through the parliament”, spokesperson Shirleene Robinson said.
"Australian Marriage Equality continues to advocate for marriage equality to be achieved through a free vote in parliament but if we are faced with a plebiscite it’s important that we have a positive and inclusive national discussion on why marriage matters to all," she said.
Former Australian Marriage Equality Director Rodney Croome quit the group last week to campaign for a free parliamentary vote, stating he was opposed to a national plebiscite.