The federal Labor caucus has voted unanimously to block the same-sex marriage plebiscite, meaning that the nonbinding vote is doomed.
The anti-plebiscite bloc of Labor, the Greens, the Nick Xenophon Team and senator Derryn Hinch will be sufficient to defeat the government’s bill in the Senate.
They will then push for a free vote in parliament on marriage equality, although the government can refuse to grant a vote in the lower house.
The plebiscite bill is before the House of Representatives on Tuesday and could be voted on in the Senate as early as Wednesday.
Marriage equality advocates are keen that the bill is debated and voted down as soon as possible to shift the debate towards whether the government will grant a free vote on same-sex marriage.
On Tuesday the attorney-general, George Brandis, urged Labor not to block the plebiscite, saying same-sex weddings could occur as early as 2017 after a plebiscite on 11 February.
“Even if the plebiscite is not your preferred method, it’s important not to let the means defeat the end,” he told ABC AM.
Brandis did not rule out a free vote on same-sex marriage in the event the plebiscite were blocked.
On Tuesday National MP Andrew Broad warned he would withdraw support for the government if there is a parliamentary vote on marriage without a plebiscite.
In comments to Guardian Australia, Broad said: “We must honour our election commitments.”
“The choice between the Coalition and Labor was clear in the election campaign. We promised a plebiscite, Labor promised a conscience vote.”
