Tasmania has become the first state to pass a motion in support of same-sex marriage in Australia.

Yesterday, Tasmania passed an in-principal support motion through the Upper House, which was originally put forth by independent Tony Mulder.

The motion was supported eight votes to five. It marks the first time a same-sex motion has passed, having been defeated twice before.

Labor MHA Lara Giddings took the opportunity to suggest that Tasmania's successful vote is further evidence that the upcoming plebiscite is not needed.

“Tasmania has taken a stand just as I’m positive a groundswell of [federal MPs] would be willing to take a stand with a free vote on the floor,” said Giddings.

Rodney Croome, a marriage equality campaigner, also noted that Tasmania's support is an encouraging sign if the plebiscite did go ahead.

“It sends the message to the Tasmanian people that our representatives are right behind marriage equality and it will encourage more Tasmanians to vote for the reform if they do end up at the ballot box,” said Croome.