Nick Xenophon has confirmed his party will block the same-sex marriage plebiscite, as Australian Marriage Equality told MPs who support marriage equality they would share the blame if their failure to work together resulted in a stalemate.

The fate of the popular vote now lies with Labor, which has indicated it is likely to vote it down.

In a statement on Monday, the Nick Xenophon Team (NXT) said: “We do not support [the marriage equality plebiscite proposal of the government].”



The statement cited two reasons: that it is a matter that parliament “can and should decide” in a free vote and the $160m cost.

“In our representative democracy we are paid to make decisions on behalf of Australians who have voted us into office,” the statement said. “This is a decision the parliament should make now.



“The [cost of the] plebiscite, which in any event could be disregarded by the parliament, could be in the order of $160m or more. We believe this money could be better spent.

“Each of us supports marriage equality and we are ready to vote accordingly.”

Just Equal and Parents and Friends of Lesbian and Gays Australia both praised the Nick Xenophon Team’s decision to block the plebiscite and called on Labor to do likewise.

Just Equal spokesman Ivan Hinton-Teoh said: ““I expect that when a plebiscite is knocked on the head the government will look again at a free vote, and even if a free vote isn’t allowed only a handful of Liberals need to cross the floor for marriage equality to pass.”

At a press conference in Canberra on Monday, Xenophon said it was an issue for the Liberal party room whether there was now a parliamentary vote.

Asked if the Nick Xenophon Team would wear blame for delaying marriage equality, he said the criticism “ought to be directed at those that oppose a vote”.

He said an ongoing community campaign and private members bill could help achieve same-sex marriage this term of parliament.

“[A private members bill] could well happen. Because it’s a tightly contested parliament, that could happen.”

On Friday the Greens announced they would block the plebiscite, citing the harm to vulnerable LGBTI people from divisive debate and polling suggesting the LGBTI community would be prepared to delay the reform if it meant avoiding the plebiscite.

The Greens, Nick Xenophon Team and Derryn Hinch all plan to block the plebiscite, meaning if Labor joins them the mechanism proposed by the government at the July election is doomed.

Labor has still not finalised its position, but its leader, Bill Shorten, continues to give strong signals Labor will block it. On Sunday he warned that the opposition was concerned Malcolm Turnbull would “stuff up” marriage equality and fail to argue the “yes” case in a popular vote.

Australian Marriage Equality (AME) chairman Alex Greenwich warned of frustration with the developing impasse and said all sides would be held accountable if change was not achieved in this term of government.

Greenwich told Guardian Australia AME had met the Coalition, Labor, Greens and NXT to ask them to work together.

AME raised options to achieve marriage equality this term, including a cross-party working group to introduce joint legislation and an inquiry to demonstrate public support for same-sex marriage.

“The community is getting increasingly frustrated by the lack of leadership from Canberra on this reform,” Greenwich said. “If MPs who say they support marriage equality aren’t able to join together and achieve it in this parliament, then they’ll all be held accountable.”

Greenwich said marriage equality had “become a political bunfight ... and that really needs to end”.

“People need to start working together. No one party has the numbers to achieve either a parliamentary vote or a plebiscite.”

Speaking to the Labor party room on Monday, Shorten said “the case has not been made” for the plebiscite “which Mr Turnbull cannot make his own MPs accept”.

“Underpinning this debate, is that for children and families in same-sex relationships: why on earth should they be subjected to a vile, negative campaign about the quality of their parents’ relationship?

“Why should teenagers and young people determining their sexuality be forced to have to undergo a public campaign of vilification?”

Shorten said the quickest path to resolving the issue would be a vote in parliament “and that’s what we will be seeking to do in coming days and weeks”.

On Monday, the education minister, Simon Birmingham, told Sky News a plebiscite was “the only way” same-sex marriage would be achieved in the next three years, after a number of Liberals warned it would be off the table if the plebiscite were blocked.

Labor’s positioning against the plebiscite has created a war of words between Liberal and Labor advocates of same-sex marriage, who are accusing each other of playing politics with the issue.

On Twitter, the Liberal MP Tim Wilson called the Labor senator Penny Wong a “hypocrite” for saying Turnbull and moderates lacked the courage to achieve same-sex marriage through a parliamentary vote.

Wong responded:

We worked to change our party's position on marriage,& we did. You've rolled over to the Right.#bringonavote https://t.co/kpmqdILv3h — Senator Penny Wong (@SenatorWong) August 29, 2016

The conservative MP George Christensen has welcomed the prospect that the popular vote to legalise same-sex marriage may never be held.



“You have to have a plebiscite,” he said. “If the Labor and the Greens don’t want one, that’s fine, no change to the Marriage Act this parliament. That suits me, it will suit a lot of other conservatives as well.”

On Monday assistant minister for social services and multicultural affairs, Zed Seselja, said it was “extraordinary and elitist” to suggest that the possibility same-sex marriage would be defeated at a plebiscite was a reason not to hold the vote.

Greens education, finance and trade spokeswoman Sarah Hanson-Young said she can “see the arguments on both sides”, including those “that desperately want to see marriage equality become a reality”.

“The last thing I want to see is politicians, particularly those that are determined to destroy the campaign for equality win.

“I don’t want to see this issue pushed off to the never-never.”