Clown pranks are no laughing matter.
The trend started in South Carolina and last night it reportedly spread to Macarthur, Camden and Wollondilly.
Sightings from across the region were posted on Facebook, but debate raged about the legitimacy of the pranks.
Facebook pages appeared called ‘The clowns are coming’ and ‘Clowning around highlands wollondilly suburbs.’
The latter has been removed.
Campbelltown Local Area Command duty officer Inspector Tara Norton told the Advertiser she was well aware of the clown hysteria in the region.
She said the officers had been briefed and were monitoring the situation.
"It's hard to tell what the clowns' motives are," she said.
"It's something so stupid to dress up as a clown to strike fear into people."
She said if the 'clowns' arm themselves, even as a prank, it was an offence and they could be arrested.
"They can be partially responsible for what could happen to someone if they are running away in fear," Inspector Norton said.
"If someone runs into the roadway or finds themselves in harm's way these people could find themselves in custody."
Inspector Norton said no clowns were arrested by Campbelltown police last night.
Camden local area command crime manager Detective Inspector Jayne Doherty said there had been a lot of talk on social media but no official reports or arrests had been made.
“In Wollondilly we heard there was going to be a fight in a park involving a clown but the police received no reports,” she said.
Detective Inspector Doherty said the events were a copy of what had happened in the United States.
“If people are doing this it can be seen as intimidation or public mischief which are offences,” she said.
“Inciting a fight is also an offence.
“If you see anybody doing these things, please report it to the police.”
Macquarie Fields Police also confirmed no arrests or reports were made.