There are suggestions that Labor will move to block Prime Minister Malcolm Turnbull's plan for a same-sex marriage plebiscite.
The Sydney Morning Herald says Mr Shorten's leadership group discussed the issue last week and while no final decision was made, they appear likely to vote the plebiscite down.
The paper reports Labor fears Mr Turnbull will put no effort into the "yes" campaign allowing the well-organised and well-resourced "no" campaign to win the vote.
Labor leader Bill Shorten has told Sunday's News Corp and Fairfax papers he's worried about the plebiscite's success with the prime minister handling the national vote.
"I'm worried Malcolm Turnbull will just stuff it up," he said.
"He stuffed up the republic referendum, he stuffed up the NBN and he stuffed up senate reforms when he promised to fix it."
There are growing concerns amid Labor's ranks the plebiscite could fail, Fairfax reports.
Opposition Frontbencher Ed Husic told the ABC a potentially divisive plebisicite should be avoided.
Meanwhile, Malcolm Turnbull is holding onto hope his same-sex marriage plebiscite will go ahead despite Labor giving the clearest indication yet it will block it.
Labor leader Bill Shorten has told Sunday's News Corp and Fairfax papers he's worried about the plebiscite's success with the prime minister handling the national vote.
"I'm worried Malcolm Turnbull will just stuff it up," he said.
"He stuffed up the republic referendum, he stuffed up the NBN and he stuffed up senate reforms when he promised to fix it."
There are growing concerns amid Labor's ranks the plebiscite could fail, Fairfax reports.
The opposition's leadership team discussed the issue in the past week, but didn't reach a decision, and it may yet go to a full caucus meeting.
Mr Turnbull said he still believed Labor would support legislation allowing the plebiscite to happen.
Arguing that it shouldn't happen because the no vote might win was the worst possible position.
"It is the most anti-democratic argument," Mr Turnbull told ABC TV on Sunday
"The Labor Party must want to delay same-sex marriage for a very long time, if they are briefing that."
He said Mr Shorten should disown that particular argument or risk destroying the credibility of his own case against holding a plebiscite.
But Labor frontbencher Ed Husic argued it was parliament's job to vote on same-sex marriage, not push responsibility onto the public.
"Don't make us go through a divisive plebiscite, which even this week people from the Irish experience said don't put people through this, don't put people through the experience of being demonised in the public," he told ABC TV.
Cabinet minister Christopher Pyne guaranteed there would be a plebiscite early next year, if it was passed through the parliament, and marriage equality if there was a 'yes' vote.
But if Labor blocked the plebiscite bill, Mr Shorten couldn't guarantee there would be a vote in the parliament, he said.
