Emergency Victoria issued eight "Hazardous Material" alerts listed within 30 minutes, with workers reportedly evacuated across the city shortly after substances were discovered.
Police in Australia said on Wednesday they are investigating several suspicious packages sent to embassies and consulates, which media reports and other officials said included the USA and British missions, in the cities of Melbourne and Canberra.
Firefighters wearing Hazmat suits entered the South Korean and Indian consulates on St Kilda Road in Melbourne shortly after 2pm (local time).
The Israeli embassy in Canberra has confirmed it also received a suspicious package.
Emergency services in Australia are responding to multiple reports of suspicious packages delivered to a number of embassies and consulates in Canberra and Melbourne.
"The circumstances surrounding the incidents are being investigated", the statement said.
United Kingdom and Swiss consulates are among several reportedly affected.
"The packages are being examined by attending emergency services", the Australian Federal Police (AFP) said in a short statement without providing further details.
Suspicious packages have sparked a major emergency response and evacuation of some foreign consulates across Melbourne, including New Zealand, with embassies in Canberra also hit.
There are unconfirmed reports that the Italian, Japanese, Egyptian and Danish consulates also received packages.
"We are liaising closely with the [Australian Federal Police] and the local authorities regarding the situation", a spokesperson said.
A spokeswoman for the service said: "We are assisting the Australian Federal Police right now with a number of incidents across Melbourne".
Staff were later allowed to re-enter the building, which was deemed safe by Vic Emergency, the collective body of emergency agencies in Victoria state, of which Melbourne is the capital.
Two days before, a suspicious package containing white powder was found at the Argentine consulate in Sydney.