29/08/2016 9:57 AM AEST | Updated 29/08/2016 6:58 PM AEST

Labor Holds Fate Of Same Sex Marriage Plebiscite

Xenophon Team is insisting on a free vote in parliament

CANBERRA – The same sex marriage plebiscite appears doomed with a key senate bloc refusing to support the Turnbull Government's effort to put marriage equality to a popular vote.

The Nick Xenophon Team (NXT) released a statement on Monday morning saying its four elected members support marriage equality, but do not support a plebiscite.

The statement says same sex marriage is a matter that "the Parliament can and should decide on as a free vote of all Members and Senators".

"In our representative democracy we are paid to make decisions on behalf of Australians who have voted us into office," the statement reads.

"This is a decision the Parliament should make now."

The NXT statement also rejects the plebiscite as expensive and non-binding.

"The plebiscite, which in any event could be disregarded by the Parliament, could be in the order of $160 million or more. We believe this money could be better spent," it said.

The Government now awaits the final decision of the Opposition, which is due to put the issue Monday to the Labor caucus.

The Government needs to pass legislation to enable the plebiscite and has warned proponents of marriage equality who are pressuring the government that, if the proposed plebiscite is scuttled, a free vote in parliament won't automatically follow.

However, Labor appears likely to join the Greens in voting against it. The Opposition Leader Bill Shorten stated Sunday it was "expensive, divisive, and non-binding" and the "second-best option", designed to "keep the right wing of his party happy".

"First of all, we should have a vote about whether or not marriage equality can be legislated in the Parliament itself," Shorten said.

On Monday night, Shadow Minister for Foreign Affairs Penny Wong told The Project Labor had "real concerns" about the plebiscite.

"What is being proposed is something that's extensive, divisive and non-binding," Wong said on the program.

"The only reason we are having a plebiscite discussion is it is because what people who oppose marriage equality wanted. Let's remember that."

Education Minister Simon Birmingham -- a moderate who support marriage equality -- insists it is all or nothing with the plebiscite.

Andrew Meares, Fairfax
Education Minister Simon Birmingham says it is all or nothing with the plebiscite

"A plebiscite is the only way they will see that change occur over the next three years," Birmingham told Sky News.

"The Coalition's policy position is crystal clear."

"People who oppose it in this parliament will only be voting for three years of delay in terms of consideration of this issue when there is an obvious pathway. The same as what Ireland went down."

Andrew Meares, Fairfax
Labor Senate Leader Penny Wong says Malcolm Turnbull lacks political courage

Labor's Senate Leader Penny Wong has told RN Breakfast Monday that same-sex marriage is a test of the Prime Minister's leadership.

"The only thing lacking here is Malcolm Turnbull's political courage," she said.

"He lacks the courage to do what he knows as right. He has lacked the courage as Prime Minister and leader of the Liberal Party to deliver marriage equality the quickest way possible, which is to enable a free vote in the parliament."

Wong insists "so-called moderates" in the Coalition should be doing more to pressure the Prime Minister to change his mind.

She described the plebiscite as a "political deceit imposed upon the Coalition" by former Prime Minister Tony Abbott and conservative Coalition members.

The Prime Minister had promised to hold the non-binding plebiscite by the end of the year, although it was being pushed back to February 2017.