A gay marriage bill in the Australian Senate was killed Thursday with a decisive blow.

Only five senators voted in favor of giving gay and lesbian couples the right to marry, while 45 disagreed.

Greens Senator Sarah Hanson-Young introduced the bill last year.

Lawmakers have previously debated marriage equality, but Hanson-Young's bill was the first to take on Australia's Marriage Act.

Before voting, Hanson-Young told the Australian Broadcasting Company (ABC) that she hoped major parties would allow their members to vote their conscience on the issue.

“But of course that's up to them. Unfortunately, we have both major parties led by conservative men who have outdated views, ideological views on this issue,” she said.

“I would like to think that members within their own caucuses are strong enough to say, 'Hey, we want to vote how we think on this issue. This is a matter of importance to us',” she added.

In the end, only the Greens voted in favor of the measure. Hanson-Young called the absence of nearly a third of the senators a “protest” vote.

“There may have been a group of senators voting to keep discrimination against same-sex couples being able to marry the one they love, but well over one-third of all senators were absent for the final vote, presumably the only form of protest open to them,” she said.

The defeat comes just days before Sydney's giant gay pride Mardi Gras this weekend.