Same-sex marriage advocates in Australia said states and territories have the constitutional power to legalise gay marriage based on a Tasmanian report. The Tasmania Institute of Law Reform has published a report in response to an upper house vote in same-sex marriage legislation in Tasmania in 2012.

The report said there is no legal obstacle to states that wish to enact marriage equality laws. It also said it remains uncertain if the High Court will succeed if it chooses to challenge same-sex marriage laws.

Ivan Hinton, national director of Marriage Equality in Australia, said the Tasmanian report only strengthens the confidence of the ACT government to create laws that will legalise same-sex marriage. The ACT same-sex marriage bill will be debated by members of the Legislative Assembly on Oct. 2013. The bill is expected to pass with the support of Australia Greens MLA Shane Rattenbury and other government MLAs.

According to the ACT Liberals, they will vote against the same-sex marriage bill because they believe it is a federal issue.

Mr Hinton urged the opposition to consider a conscience vote on the same-sex marriage bill after the Tasmanian report was published. He said ACT Liberals leader, Jeremy Hanson, had mentioned that many Canberrans will benefit from the passage of the same-sex marriage bill.

The Tasmanian report addressed the concern regarding a High Court challenge to the proposed bill. The report said there is no way to know if the High Court can rule if a same-sex marriage law will be enacted in Tasmania because of inconsistent federal laws. It also claimed that the Commonwealth of Australia has the most right to challenge any same-sex marriage bill enacted in states and territories. It also found that while state-based same-sex marriage laws may be open to a constitutional challenge, the challenge doesn't have to hinder any move to promote legislative change.

Prime Minister Tony Abbott will have to decide whether the proposed marriage equality law should be blocked. He has the power to challenge the ACT law in High Court or not to allow it by putting it to a vote in both Parliament houses.