Postbox party urges millennials to vote

As the same-sex marriage postal survey enters its final weeks, an innovative campaign has sprung up to push millennials out the door and to the postbox in order to have their say.

The tailored, ten-day social media campaign is releasing a series of videos designed to energise digital-savvy millennials to vote, with the added allure of winning flights overseas.

"Effectively, it's a digital postbox party," organiser and FolkTale CEO Sarah Mak told AAP on Saturday.

"It's all about this weird and wonderful notion of getting the postbox front of mind for this demographic, particularly men."

Earlier this week, a Newspoll found that nearly seven in 10 people between 18 and 34 support same-sex marriage but lag behind older age-groups in returning completed ballots.

"We know young people are much more likely to support a 'Yes' vote, so it's crucial they post their ballot papers this week," the Equality Campaign's Tim Gartrell said in a statement on Friday.

The Postbox Party initiative was specifically timed for the tail-end of a long campaign and received the endorsement of the Equality Campaign.

Ms Mak said of the Equality Campaign: "They identify that millennials and young voters, in particular, are such an important part of the matrix of why this is going to be successful."

Two business class flights to Los Angeles, donated by Qantas, will be awarded to the winners of a competition where people submit a video of themselves in front of a postbox.

"It's that notion of travel and adventure and the fact that everyone is so digitally connected," Ms Mak said.

"So we created something that was built by millennials for millennials."

The postal survey officially closes on November 7, but the Australian Bureau of Statistics has asked that responses be sent by October 27 to ensure they are counted.