Protesters plan to block the opening of the Land Forces exposition at Melbourne Convention and Exhibition Centre on Wednesday morning, with more than 25,000 activists expected to disrupt the city centre.
The state's treasurer has warned anyone who does not need to be in the area to stay away.
"If you have no business being there, if you're not there protesting, I wouldn't encourage anybody to be there," Tim Pallas said on Tuesday.
Yarra Trams has warned commuters of disruptions to several city-bound services, including the routes 96 and 109.
Mr Pallas said police had asked the state government for additional funds to cover the event, estimated to cost $10-15 million.
Victoria Police expects it to be their biggest operation since chaos surrounding the World Economic Forum in 2000, with hundreds of regional officers travelling to Melbourne for the event, along with general duties officers and specialist police.
These include the Public Order Response Team, Highway Patrol and Mounted Branch.
A police spokesperson said major efforts were under way to ensure the "highest level of safety and security" at the event.
Disrupt Land Forces spokeswoman Jasmine Duff said the protest was triggered by the government's stance on the conflict in the Middle East.
"We're protesting to stand up for all those who have been killed by the type of weapons on display at the convention," she said.
"Many of the weapons inside the convention centre are advertised as battle-tested. In the context of Israeli weapons firms, which are present, this means tested through killing civilians in Gaza."
The Land Forces International Land Defence Exposition runs from Wednesday to Friday.
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