Local media has reported parcels were delivered to consulates and embassies of the UK, the United States, New Zealand, Germany, Korea, India and Switzerland.
Emergency services attended consulates across Melbourne's central busy district and the inner city.
In Australia, suspicious packages have been delivered to several embassies and consulates in Canberra and Melbourne.
There are unconfirmed reports that the Italian, Japanese, Egyptian and Danish consulates also received packages. "The circumstances are being investigated", the official statement reads.
It is understood at least seven Melbourne buildings have been evacuated.
The packages were being examined by "attending emergency services", the Australian Federal Police (AFP) said in a statement on Wednesday, without providing additional details.
Officials at the US and British consulates separately confirmed suspicious packages had been received.
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The Melbourne fire brigade and Australian Federal Police are now investigating.
Sky reported that the scare coincided with the USA embassy's hazmat training, which had been booked for months.
"A worker at the Pakistani consulate in Melbourne opened one of the packages about 10am on Wednesday".
Addresses for the events included Market Street, Bourke Street, Middleton Lane, William Street, and St Kilda Road in Melbourne, Elgin Street at Carlton, and Yertchuk Avenue at Ashwood.
One firefighter was seen outside the South Korean consulate carrying a large plastic bag with the word "asbestos" written on it.
Staff members were later allowed to re-enter the building, which was deemed safe by Vic Emergency, the collective body of emergency agencies in Victoria, of which Melbourne is the capital.
The incidents come after Sydney's Argentinian consulate was partially evacuated on Monday after reports of a suspicious substance. Results from police testing have yet to be revealed.