by Claire Bickers
SAME-sex marriage faces its final test in Parliament this morning when politicians vote on final changes to the historic bill proposed by Tony Abbott.
Labor predicts the bill can pass parliament as early as 2pm today - the final scheduled sitting day of the year - if no last-minute changes to the bill are made.
But if any changes are approved, both houses of parliament will be forced to remain in Canberra tomorrow until the bill is passed.
"If any of the amendments are carried, and I don't think they will be, we have a problem," Labor frontbencher Tony Burke told Sky News this morning.
"I would be surprised if any of the amendments get up and certainly if they were to get up, we could potentially be here for quite a while."
Mr Burke predicted same-sex marriage could be made legal in Australia shortly before Question Time at 2pm, or about an hour after the session at 4pm.
"There's no desire to gag the debate - but I also don't think there's any desire from people who are moving amendments to filibuster and try to make it go forever," he said.
If any amendments do pass, the bill will be sent back to the Senate, where it will be knocked back before going back to the House of Representatives a second time.
Last-ditch efforts from Mr Abbott and the Greens to change the bill could result in a delay.
Magda Szubanski and fellow leaders of the Yes campaign gathered on the lawns of Parliament House this morning to urge politicians to pass the bill without delay.
It comes after Queensland crossbench MP Bob Katter delivered a bizarre, rambling speech on same-sex marriage in the House of Representatives last night.
Mr Katter spoke about everything from slavery to "boys in dresses", Christianity and Gianni Versace, while making wild accusations that gay people were "murderers" and "responsible for giving AIDS" to society through donating blood.
He also said he wasn't anti-homosexual.
Mr Katter was one of the last MPs to speak on the bill. About 120 others have spoken in the past three days.