© 9NewsAn apparently foil-wrapped object was thrown through the window of WA Premier Mark McGowan's electorate office.
A man has been arrested after a suspicious package wrapped in foil was thrown through the window of Western Australia Premier Mark McGowan's electorate office.
It is understood a man flung the object through the window of the premier's office in Rockingham about 4pm local time yesterday and then fled the scene.
The office was immediately evacuated and one staff member was taken to hospital as a precaution.
READ MORE: Driver provides fake details after allegedly hitting six-year-old boy
A similar package was also discovered at the electorate office of federal MP Madeleine King, with the office also evacuated.
Neither Ms King or Mr McGowan were in the area at the time, but staff were left shaken.
Video: SA Police investigating deadly shooting of 49-year-old man (Sky News Australia)
SA Police investigating deadly shooting of 49-year-old man
![UP NEXT]()
UP NEXT
Mr McGowan said they were still not aware what had been in the package.
"We're obviously in a very heightened environment at the moment, I'd just urge everyone to behave appropriately," he said.
© 9NewsMr McGowan was not in the office at the time.
A 67-year-old man has been arrested and is now assisting police with their enquiries.
Western Australia is set to head to the polls on Saturday, for a state election Mr McGowan's Labor is expected to overwhelmingly win.
The attack on Mr McGowan's office follows a death threat the day prior, when a man at a Perth early polling booth told people he had a gun and he planned to shoot the premier.
A major Labor billboard was also graffitied in Nazi symbolism.
Police are investigating the incidents.