Officers were monitoring people who had left the party and were walking along Glenbawn Drive when some of them started throwing cans, bottles and rocks at the officers.
Officers arrested several people, who have since been charged with a range of offences, including a 12-year-old boy who is facing a charge of assaulting a public officer.
He is due to appear in Fremantle Magistrates Court on April 21.
An 18-year-old woman from Beaconsfield has been charged with assaulting a public officer, disorderly behaviour in public, disorderly behaviour in a police station and failing to provide personal details.
A 14-year-old boy and a woman, 19, have both been charged with disorderly behaviour. An 18-year-old man from White Gun Valley has been issued with a criminal code infringement for disorderly behaviour in public.