WA police responded to reports of a man making a disturbance at the office of state MP Hannah Beazley in the inner-Perth suburb of Victoria Park on Wednesday afternoon.
"It was reported that the man was making verbal threats while in possession of what has been described as nunchucks," police said in a statement.
Officers later found a 56-year-old man in the nearby suburb of Bentley, and said he was assisting them with their inquiries.
No one was injured in the incident, police said.
Ms Beazley said she was aware of what had unfolded and her staff were understandably shaken.
"This afternoon, staff within my electorate office were faced with a confronting situation when a member of the public entered the office armed with a weapon," she said.
"Fortunately, no one was injured during the incident.
Ms Beazley said her focus right now was on the welfare of her staff members.
"Everyone has the right to go about our lives free from the fear of violence, at work, at home and in the community."
Ms Beazley is the Labor state minister for local government and the daughter of former federal Labor leader Kim Beazley.
The incident comes days after federal member for Indi Helen Haines was struck by a four-wheel-drive vehicle outside her electorate office in northern Victoria on Monday afternoon.
Police allege Brendan Nugent, 43, deliberately drove the vehicle into Dr Haines, who remained in critical condition in hospital on Wednesday after both her legs were amputated.
The incident has sparked a nationwide debate about whether public officials are sufficiently protected from threats against their safety.
