"My prediction, and it's only a prediction, is that in the plebiscite, whichever of the two forms it takes, more people will vote yes than no", he told the ABC's 7.30 program.
The government has assured Australians living overseas they will be allowed to have their say.
The opposition Labor party has repeatedly called for a simple vote in parliament to approve the same-sex marriage, which consecutive polls show most Australians support.
Marriage equality would also cast doubt on whether religious schools could teach children that marriage was exclusively between a man and a woman, Mr Shelton said.
Bill McLennan, Australian Statistician and head of the Australian Bureau of Statistics between 1995 and 2000, said he doubted the ABS had the authority to conduct the vote.
If this happens, said Mr Turnbull, the government will organise a postal ballot pursuant to which all voters will receive voting materials.
The Liberal Party held a crisis meeting late Monday to resolve infighting and rejected a push to allow lawmakers to decide the issue now.
"If that were to fail, the government believes that we have a legal and constitutional way forward that gives the Australian people a say on whether or not the definition of marriage should be changed".
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They were in the National Assembly as members of the ANC, who had to carry out ANC decisions and policies, Maphatsoe said. The motion, which was introduced by the opposition Democratic Alliance, needs 201 out of 400 votes to succeed.
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As of Saturday, Cutler was reluctant about a possible return to football, although he hadn't made any decision with certainty. Gase was Cutler's offensive coordinator for much of the QB's time in Chicago, and the two apparently have a good relationship.
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Last August he was taken to hospital with wrist injuries , which prison authorities said he sustained after falling in his cell. A year ago he received treatments after he sustained cuts to his wrists, which he said were the result of a fall in his cell.
Conservative MP Craig Kelly said after the meeting the Senate negotiating team should be given "wider latitude" to attempt to get the original plebiscite policy through the Senate.
Prime Minister Malcolm Turnbull said he expected the public would support marriage equality in the so-called plebiscite, and that he would personally campaign for a "yes" vote.
The proposed postal vote would cost more than 122 million Australian dollars (96 million dollars), Turnbull said.
BALLOT PAPERS to be sent out from September 12 and the result finalised by November 15.
Late previous year, the upper house Senate rejected a government proposal on the matter, with opponents saying they believed it was best dealt with by a free vote in parliament. He added, "I'm a strong leader". "Strong leaders carry out their promises, weak leaders break them", he told reporters.
If the Senate again blocks the plebiscite, the government intends to hold a voluntary postal plebiscite by November 15.
This is looking likely with the Greens, Labor and the Nick Xenophon Team all indicating they will once again knock back the bill, which Opposition leader Bill Shorten labelled a delaying tactic on Tuesday morning.
Ms. Butler said it was "utterly ridiculous" to put in place "all these processes" before "they will even let us have a vote in the Parliament". The upper house Senate rejected a government proposal on the issue, stating a free vote in parliament was the best way of dealing with the matter. Efforts to adopt marriage equality in some jurisdictions, such as a 2013 effort in the Australian Capital Territory, have been short-lived and unsuccessful.