The Nick Xenophon Team will join the Greens to vote against the government's marriage equality plebiscite, leaving the controversial proposal seemingly dead in the water.
In a statement on Monday morning, the three senators and one lower house MP for the Nick Xenophon Team released a statement clarifying they do not support the plebiscite, giving two reasons for their opposition.
"In our representative democracy we are paid to make decisions on behalf of Australians who have voted us into office. This is a decision the Parliament should make now," the statement reads.
The MPs also believe the $160 million could be better spent.
The government currently has 37 votes for the legislation in the senate, and needs 39 to pass it.
With the Greens and Nick Xenophon now vowing to vote against it, the fate of the plebiscite lies squarely in the hands of the Labor party.
Labor leader Bill Shorten has deployed increasingly hardline rhetoric against the plebiscite, briefing the Sunday papers that Labor would likely vote down the proposal.
Speaking to the Labor partyroom on Monday morning, Shorten said the government had failed to make a compelling case for the national vote.
"Australians can be fined for not voting in the plebiscite, but no Liberal or National MP has to vote according to the plebiscite," he said.
"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?"
However, Shorten has left the door ever-so-slightly open to voting for the proposal, saying that Labor must see the legislation before making a final decision.