"Tony Abbott's attempt to block same-sex marriage by taking the ACT Government to the High Court will fail because Australians want change and are sick of his last century and discriminatory attitude," Australian Greens Leader Christine Milne said.
"Give up Tony Abbott. You are not going to thwart the will of the Australian people to end marriage discrimination.
"At some point Tony Abbott will have to admit that he supports discrimination against LGBTI people in Australia. It is wrong.
"Marriage equality is well and truly on the agenda in Australia. The Greens will continue to drive it in every parliament.
"I call on the Labor party to recognise this as a matter of discrimination, not conscience, and support the Greens bill in the Senate.
"Unlike the other parties, the Greens believe there is no place for discrimination in Australia on any grounds, whether that is gender, race or sexuality.
"I congratulate the ACT Government and the ACT Greens for pursuing marriage equality and for their commitment to robustly defend the High Court challenge."