WA Police have warned hooligans dressed up as clowns that carrying dangerous weapons in suburban streets will not be tolerated, after sightings were recorded in more than 20 suburbs overnight.
Facebook page Perth Clown Watch catalogues areas where the menacing jokers may be frequenting, and named Kwinana, Ballajura, Dianella, Mount Pleasant, Pierra Waters, Claremont, Lynwood, Wanneroo and Woodvale as weekend clown hot spots.
The bizarre - and as yet unexplained - phenomenon appears to have started in South Carolina in late August and arrived in WA over the past month, with photographs emerging last week of a frightening looking clown at at Mandurah shopping centre.
With reports of more and more clowns arming themselves with machetes, hammers and old cricket bats, a WA Police spokesman said they would take action if they believed them to be causing fear to the public.
"Even to take away the clown aspect of it, anyone who is going around with a baseball bat or machete to cause fear would be in trouble," he said.
Two clowns were spotted in the Rockingham area on Saturday evening following an alleged "clown party", and one was reportedly armed with an "old chainsaw".
Members of the public have also complained about clowns allegedly taking mobile phone numbers from open Facebook profiles, and anonymously calling personal phone numbers.
"Wanting to warn people... the number [redacted] has called me and my other friends (who weren't with me) numerous times, and just played out continuous circus music with evil clown laughs," one victim said.
"If you don't answer, they send vicious voicemails claiming "you're next", "not answering? Won't stop us.""
Police around Australia have warned the public against becoming involved with the craze, calling those dressing up "stupid".
There was initially speculation the clown "epidemic" might have been part of a plan to promote a new Stephen King movie but those rumours were quickly dispelled.