A man is believed to have been injured by a machete during a violent confrontation in Dianella overnight.
Police were called to a soccer club on Homer Street at 2.16am after reports that people were fighting.
"Local Police, Regional Operations Group and a Canine unit attended," a police spokesperson said.
"The crowd dispersed once police arrived."
Police said that although vehicles were searched, officers did not find any weapons.
"A 23-year-old Joondanna man received a cut hand, believed to have been caused by an offender who had been armed with a machete," the spokesperson said.
He was taken to Royal Perth Hospital by ambulance and was interviewed by police.
"At this point he has given limited information to police and inquiries are continuing," the spokesperson said.