Roundup: Aust'n Labor Party confirms opposition to same-sex marriage plebiscite

Australia's opposition Labor Party has officially announced it will block the legislation for a same-sex marriage plebiscite, or public vote, which was set to be held in February.

Following weeks of speculation that Labor would block the legislation on grounds that it would be divisive and a "shocking waste" of 160 million U.S. dollars, Labor MPs met in Canberra on Tuesday and decided they would join Greens and Independent MPs in blocking the legislation in the Senate, effectively leaving the plebiscite dead in the water.

The Turnbull government has said if Labor blocks the legislation, same-sex marriage would not be revisited for "years," but following the decision, Opposition Leader Bill Shorten said the issue went beyond politics.

"Experts have explained to Labor that a plebiscite would cause harm to gay and lesbian people, particularly young people," Shorten told the press on Tuesday following the caucus meeting.

"Having met these families, I could not in good conscience recommend that the Labor Party support the plebiscite for same-sex marriage. The caucus unanimously resolved to oppose the plebiscite legislation ... therefore the Labor Party will oppose the expensive, divisive plebiscite."

Earlier on Tuesday, Deputy Opposition Leader Tanya Plibersek said Labor was still a staunch supporter of same-sex marriage, but said a divisive and expensive plebiscite was not the way to address the issue. Labor had previously said "no" campaign for the public vote could negatively affect the mental health of LGBTI Australians.

"We've spent the last three weeks since we saw the plebiscite legislation that was introduced late in the last sitting week, consulting with members of the gay and lesbian community," Plibersek told the Australian Broadcasting Corporation (ABC) on Tuesday.

"Those several extra weeks of consultation on the specific legislation have not reassured us one little bit. In fact, they've increased our concerns.

"We are concerned about the mental health impacts of people, particularly young people who are particularly vulnerable to the sort of criticism of themselves, their lifestyles, the people they love, that we're worried about."

Plibersek said Labor was prepared to introduce legislation which would allow a conscience vote in Parliament on the same-sex issue.

"This could be changed this week. There's legislation before the Parliament right now," she said.

"If there was a desire from the government to see marriage equality happen - and we've got a Prime Minister and an Attorney-General who say that they support marriage equality - if they really support marriage equality, this could be through both Houses of Parliament in a week."

Attorney-General George Brandis said Labor would likely get a second chance to pass legislation for a plebiscite, and said the government is offering a real solution which could result in the legalization of same-sex marriage by early next year.

"It's all very well for Tanya Plibersek (and Labor) to speak about her commitment to marriage equality, but when it comes to actually taking the steps to ensure that we achieve that outcome, Labor is nowhere to be seen," he told the ABC.

The coalition is still expected to introduce the legislation into Parliament despite not having the numbers on paper to pass it through the Senate. Endit