The international weapons expo, which runs from today through Thursday, is expected to attract thousands of visitors, with nearly 1000 organisations from 60 different countries hosting exhibits.
Police were visible in force outside the venue this morning, and commuters have been warned to expect delays on Mounts Bay Road, with parking closures in effect from today through to Thursday.
Officers have been given special powers to keep the peace following violent protests against the event in Melbourne two years ago. Around 12 people have been excluded from coming near the Perth event.
A peaceful anti-war protest is planned for this afternoon, with demonstrators to march from Yagan Square to Elizabeth Quay.