Labor MP accepts postal vote reality

Shadow attorney-general Mark Dreyfus says it's time to launch the 'yes' campaign in the same-sex marriage postal vote.

Shadow attorney-general Mark Dreyfus says it's time for the 'yes' campaign on same sex marriage. (AAP)

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.