The Greens have actually introduced a private members bill to legalise homosexual marriage in the past (believe was early 2000's, not long after the law was changed to be exclusive for males and females only). It was defeated by a majority in parliament (as will the any new bill introduced).
I wouldn't say I would "love" to see it introduced, but I believe it should be legal (the only reasons are religious based, which should not dictate a legal process in Australia).