Australia's National Rugby League (NRL) has voiced its support for marriage equality ahead of a national public postal vote on the issue.

The league's backing came after an appeal from Ian Roberts, a former professional rugby player who came out gay in 1994 and is widely credited as Australia's first out professional athlete.

In a letter last week to NRL CEO Todd Greenberg, Roberts called on the league to back the Yes campaign.

“As you know, I came out publicly 25 years ago,” Roberts wrote. “The ARL [Australian Rugby League] failed to make the most of that moment. They could have been on the front foot, leading the way for all sporting bodies, and not just sporting bodies but for all major corporations. The ARL chose to ignore that opportunity because it was an awkward conversation to be having back in 1994.”

“It’s not awkward any longer – it is a necessary one. I don’t want the game I love to again miss this moment in history. This is about being brave. It’s about doing the right thing. It’s about saving lives because that’s the power our game has. It is a game for everyone,” he added.

Greenberg cited inclusiveness in his public response.

“There is a place for everyone in rugby league,” Greenberg wrote. “It might be as a junior, as a volunteer, as a match official or as an NRL player. And we need to treat everyone equally both on and off the field and that’s why we will publicly support the same-sex marriage proposal.”

Roberts told The Sunday Telegraph that he's “never felt so proud” about rugby.

“This will save lives,” Roberts said. “This is a moment in time that will be remembered forever.”