The Mandurah Forum was in chaos this morning when a man was arrested at the front entrance after allegedly punching a security guard.
Three police officers, paramedics and shopping centre security guards attended the incident and stayed with the man until he was taken to Peel Health Campus.
A Mandurah Forum security guard told the Mandurah Mail the man entered the shopping centre this morning and was acting erratically with a mask covering his face, before being arrested by police.
He said the man had re-entered the Forum and behaved in the same manner before punching a security guard from behind, about 11.35am.
The man was escorted from the premise by two security guards before being held until police arrived.
The Forum security guard said guards dealt with this behaviour "all the time".
"A big incident happens once or twice every month," he said.
"They are the crackheads - the ones using drugs.
"We end up knowing most of them."
WA Police have been contacted for comment.