Police are investigating a fourth suspicious mail package and have cordoned a Riverton shopping centre just hours after the Perth Mail Centre was evacuated.
WA Police spokesman Sam Dinnison said police were investigating a report of a suspicious mail item being delivered to an office at the Riverton Forum in Parkwood and had closed off areas of the shopping centre as officers make inquiries.
It comes after the Tactical Response Group Bomb Response Unit was deployed to the Perth Mail Centre on Boud Avenue, Redcliffe after three suspicious packages were found.
Mr Dinnison said the packages had been deemed "suspicious" because of the nature of the words written on them and confirmed the centre had been evacuated and Dunreath Avenue closed.
Police have not commented about whether the mail item found at Riverton is linked to three other packages that led to the lockdown of the airport mail centre.
Perth Airport has not been evacuated and Brearley Avenue is open all the way to the domestic airport
An Australia Post statement confirmed the facility had been evacuated and the package was being tested, but said the safety of their staff was taken extremely seriously.
Mr Dinnison urged people travelling to Perth Airport to allow extra time due to the expected build-up of traffic in the area.
An Australia Post spokeswoman said authorities had evacuated the Perth Mail Centre as a precaution after suspicious mail packages were found. Tests of those items were being conducted.
"Australia Post takes the safety of all our staff extremely seriously," she said.
"There may be some minor mail delays in Perth due to the evacuation but we are working hard to ensure minimal disruption occurs."
