The state election is probably the last thing on gay men's minds when they're looking for casual sex.

But in what is believed to be an Australian first, the Greens will advertise on gay hook-up app Grindr, targeting voters in the marginal and diverse seat of Prahran.

Greens candidate for Prahran Sam Hibbins said the smartphone app, which connects men for casual sex, was an innovative way of reaching the gay community.

"It offers us a platform where we can reach the gay community in Prahran," the 30-year-old Stonnington councillor said.