SOS: The creepy clown craze has swept Australia. And there is a solid theory why.

Coulrophobics, you might want to stay indoors for a while. You know those utterly disturbing clown sightings that have been happening in the US lately?

Well, they’ve made it Down Under.

Victoria Police have been forced to issue warnings, following numerous reports of people in clown costumes terrifying members of the public.

“The clown purge appears to be a copycat of incidents being seen in the USA recently,” read a statement posted to social media.

“Any intimidating and threatening as well as anti-social behaviours will not be tolerated and will be investigated by Police.”

A costumed man spotted in Mandurah, WA. Image: Facebook - Mandurah Clown Sightings.

Dozens of dedicated social media accounts have sprung up to catalogue sightings of the menacing Bozos.

A quick scroll through a Facebook page called Clown Sightings Australia (which already has close to 5000 followers), reveals images of costumed people allegedly snapped on the streets of Sydney, Melbourne, south east Queensland and Western Australia.

One clown was pictured loitering outside a fast food restaurant in the Campbelltown area of Sydney, while a group of them have reportedly been terrorising shoppers outside supermarkets in Mandura, WA.

A red-headed clown reportedly seen near Frankston High School. Image: Facebook - Clown Sightings Australia.

Meanwhile, one female resident from Warwick, Queensland, says she was chased 500m through the streets by a man in a clown mask.

"Police have been notified," Ebony Perry wrote on Facebook, according to The Sunshine Coast Daily.

"It left me shaking. I couldn't imagine how much it would scare a child."

The sinister craze began in the US state of South Carolina with reports that people dressed in clown costumes were trying to lure children into the woods.

The phenomenon attracted international headlines and sparked minor hysteria across the US, as well as suspected copycat activity in Alabama, Georgia and Pennsylvania.

Even Stephen King, author of It, the horrifying book/movie that is at the root of many people's clown-related fears, has urged poeople to keep calm.

The sightings were even raised during a White House press briefing last week, in which press secretary Josh Earnest said while President Obama hadn't been specifically briefed on the issue, "this is a situation that local law enforcement authorities take quite seriously".

There has been rife speculation the craze is part of a guerilla marketing campaign to promote the upcoming movie release of King's It, which features an evil clown named Pennywise.

So we might be looking at a PR stunt and bored teenage copycats, but - let's be honest - we'd still rather not come across one late at night.