Equal marriage protest (PETER PARKS/AFP/Getty Images)

LGBT campaigners and politicians have expressed shock at an anti-gay poster ahead of Australia’s same-sex marriage vote.

The poster shows a child with their head in their arms, while two fists hold rainbow coloured belts.

The shocking anti-gay ad, seen in Melbourne, Australia, boasts the words ‘stop the fags’ in bold, white print, clearly visible from a distance.

Critics say the poster proves the upcoming marriage equality ballot will allow for an outpouring of bigotry.

The poster uses nonsense stats to claim that the children of gay parents are disproportionately abused.

It claims that “92% of children raised by gay parents are abused”.

It also claims 51% have depression, and 72% are obese.

It is believed the poster originated on a Nazi website and was subsequently printed out and pinned up in the Heffernan Lane area of Melbourne.

Australian Labor leader Bill Shorten labelled it “disgusting”, saying: “Labor opposed this postal survey because we feared exactly this kind of hurtful filth would emerge.

“This kind of garbage isn’t ‘debate’, it’s abuse.

“I’m so sorry that LGBTI Australians have to put up with it. Let’s make sure there’s an overwhelming ‘Yes’ vote in response.”

EXPLAINED: What the hell is going on in Australia’s same-sex marriage debate?

Australian PM Malcolm Turnbull, who is on the right, is planning to hold a postal vote on same-sex marriage later this year, after coming under pressure from his own MPs to block an equal marriage bill within parliament.

Though the vote will not be legally binding – it is a national postal ballot to inform the government – the latest poll on the topic looks like there is going to be a very clear result.

The Australian polled voters on their intentions for the upcoming plebiscite on same-sex marriage.

According to the newspoll, the pro-equality ‘Yes’ campaign has a huge lead.

63% of respondents said they intend to back yes in the vote, while 30% say they will vote against the proposal, and six per cent remain uncommitted on the issue.