Police are investigating an armed robbery in Perth's south-east where a man was beaten up by a group of people in a park who then stole his car.

Police said around 8:15pm on Thursday night a 24-year-old man had finished playing basketball in Kuhl Park on Westfield Road, Camillo when he was approached by a group of people as he walked to his car.

Witnesses are urged to contact Crimestoppers. Credit:Georgia Matts

Police said the four men and one woman assaulted the man, with one of the group carrying a screwdriver.

The victim was knocked to the ground and received minor injuries to his hand, his shoulder and to his leg.