One of the oldest football clubs in Australia today swapped its traditional colours for a rainbow jumper in a show of support for gay players.

The University Blacks' "Gay, that's ok" campaign is the first of its kind in the Victorian Amateur Football Association.

Players hit the field today in jerseys accented with rainbow stripes as part of the cause.

University Blacks wore the jumpers in today's game. (Supplied)

Rainbows were also painted on the 50-metre line to match the jerseys.

The initiative was inspired by the club’s former player Lachlan Beaton, who hid his sexuality for fear of being ostracised.

"We just think that AFL and sporting clubs can do a lot in this space, by physically coming out and saying it's ok to be gay," Mr Beaton's twin brother Charles said.

Former Geelong player Simon Hogan, current Hawthorn player Matt Spangher, AFL CEO Gillon McLachlan and former Yarra Glen club footballer Jason Ball are among those supporting the cause.

The concept looks likely to be taken even further next year, with St Kilda hoping to play a pride match as part of its 2016 AFL fixture.