Three police officers have been assaulted at the Listen Out Concert at Joondalup on Sunday after at least 200 people jumped fences and overwhelmed the event's security.
The dance music festival at the HBF Arena featured artists like Anderson.Paak and Claptone and had a large turnout of concert goers inside - but many people rushed the fences to get in.
Police said the event's security called for assistance at around 3:20pm after a number of people began throwing rocks at patrons and pushing on the fences to get in.
Video footage of the incident posted to Facebook shows scores of people jumping fences at the event's perimeter, running through an area patrolled by security guards and attempting to climb over the inner barricades.
Police said when they arrived officers moved to disperse a group of around 300 people, some of whom began throwing objects.
Police allege that during the incident three officers were assaulted, with one officer bitten and two officers physically assaulted.
A 23-year-old man from Roleystone has been charged with disorderly behaviour, while a 22-year-old male from Armadale has been charged with Assault Public Officer.
A 22-year-old female from Kalamunda has been charged with Obstructing Police and Assault Public Officer and a 20-year-old woman from Kalamunda has been charged with Assault Public Officer.
They will all appear the Joondalup Magistrates Court at later dates.
The following video contains explicit language: