Labor frontbencher Mark Dreyfus says it's time to get behind the "yes" campaign and turn out to vote in the same-sex marriage postal ballot.
The federal opposition has been vigorously fighting the government's plan to put the issue to a national vote, saying it would unleash bigotry and is a waste of $122 million.
"We might not like it, but the marriage equality postal vote is happening - and we have to win it. Enrol now!" the shadow attorney-general tweeted on Wednesday.