A young gay woman directing traffic at the Royal Show is distraught after someone posted anti-marriage equality stickers on the signs she was standing in front of.
Jasmine Andersen shared a picture of a massive sticker with the words "keep marriage man and woman", on a sign where she was directing traffic on Second Avenue outside the show on Thursday.
"Does anyone by any chance know who is responsible for this hatred?," she said.
"I'd love to speak to them."
A person posted online saying the stickers had popped up throughout Claremont.
Ms Andersen told WAtoday it was sad "that thousands of people walked past that sign and may have been impacted by one person's opinion".
"Who knows what effect it will have on the community," she said.
Perth-based Greens senator Rachel Siewert said the anti-marriage equality sticker showed how damaging a plebiscite on gay marriage can be before it has even begun.
The Greens passionately oppose a Turnbull government plebiscite on same-sex marriage, arguing people's rights should not be subject to a popular vote that could unleash homophobia and hatred.
"Young LGBTIQ people, some of whom may still be coming to terms with their sexuality, do not need to see hurtful slogans when entering or exiting the Perth Royal show," Ms Siewert told WAtoday.
"Events like the Royal Show should be a safe space for everyone. For the LGBTIQ community who saw this sign, they're basically being told 'you're not welcome here'.
"This is a disgraceful example of how the plebiscite can be hurtful before it has even begun.
"Advocates for the plebiscite say that debate would be civil, but this is a debate that argues the rights of a marginalised group who are asking for equal rights. Hurtful materials being distributed already removes any argument that a genuine civil debate can occur."
The Town of Claremont and the Royal Show have been contacted for comment.