Opposition Leader Bill Shorten will meet with Labor’s caucus today to deliver a verdict on the same-sex marriage plebiscite. Picture: Kym Smith

Labor caucus members shot down the proposal after meeting at Parliament House this morning following Opposition Leader Bill Shorten warning the plebiscite would inflame tensions and put gay Australians at risk.

This means the bill is almost certainly doomed to fail in the Senate with the Greens and key crossbenchers previously stating their opposition to the plebiscite.

It happened shortly after Nationals MP Andrew Broad announced he would withdraw his support from the Government if it didn’t use a plebiscite to bring about changes to the Marriage Act.

“The Government that I am part of, and will remain a part of, is conditional on the fact that the only way that there will be a change to the Marriage Act in this Parliament is a plebiscite and my position as a member of the government is very clear on that,” Mr Broad told media this morning.

“My support for the Government is conditional that we honour our election commitments. I’m making it very clear here.”

The Government today released amendments to the Marriage Act, which will lay the foundations for ongoing debate should the same-sex marriage plebiscite go ahead.

Changing the definition of marriage from “a man and a woman” to “two people”, recognising foreign same-sex marriages in Australia and allowing marriage celebrants the right to refuse to marry a same-sex couple are some of the key changes.

Opposition Leader Bill Shorten and Deputy Leader Tanya Plibersek met with stakeholders and activists of the LGBTI community in Surry Hills. Picture: News Corp Australia.Source:News Corp Australia

Mr Shorten, Shadow Attorney-General Mark Dreyfus and Shadow Assistant Minister for Equality, Terri Butler met with LGBTI families in Canberra following Labor’s announcement that it would block the plebiscite.

During a press conference, Mr Shorten said experts had “unequivocally” explained to Labor that the plebiscite would cause harm.

“Having met these families, having listened to their stories, I could not in good conscience recommend that we support the plebiscite on marriage equality,” he said.

Mr Shorten said the caucus had unanimously resolved to oppose the marriage plebiscite.

“The Labor party will in Parliament oppose Malcolm Turnbull’s expensive, divisive plebiscite,” he said.

“Children do not need to go to school... And have the integrity of their parent’s relationship challenged.

“This country does not have the right in a plebiscite to pass judgement on the marriage and relationships of our fellow Australians.”

Mr Shorten said marriage equality could be available today by having a free vote in the Parliament.

He said Labor would continue to press its case in the days and weeks to come.

The government has maintained a plebiscite is the quickest way to achieve same-sex marriage, however Labor argued the $175 million exercise — including $15 million set aside for the yes and no public information cases — is a waste of taxpayers’ money.

Deputy Opposition Leader Tanya Plibersek told ABC News this morning the plebiscite was a “wasteful exercise” for “something that should be determined by the parliament”.

“The High Court has said that the Australian Parliament is the proper place to determine the plebiscite,” Ms Plibersek said.

“We didn’t have a plebiscite when John Howard overturned the Northern Territory’s voluntary euthanasia laws. We have never had a plebiscite.”

Cabinet minister Simon Birmingham threw Labor a lifeline on the plebiscite, saying the Government would even consider suspending the $15 million “yes” and “no” campaign.

But Ms Plibersek slammed the offer as an “absurd last-minute effort” to “try and suggest that they have been interested in consultation”.

Labor’s caucus will meet today before formally announcing its position on the same-sex marriage plebiscite. Picture: News Corp Australia.Source:News Corp Australia

“I don’t think it is sincere. I think it is very typical of the Attorney-General to release legislation last night at 11pm and say, ‘We want your answer today on what we released at 11pm last night.

“It is not well handled at all.”

Speaking to ABC Radio, Attorney-General George Brandis said Labor had been difficult to deal with throughout the process.

He said members had been consulted several times on what changes they would like to see enacted, but had refused to answer questions.

When asked how serious he was about implementing same-sex marriage in Australia, Senator Brandis said he was the first Attorney-General in government who had prosecuted the issue.

“We could have this outcome four months from today if the Labor Party put political games aside and really committed to this issue,” he said.