The Avalon Airshow kicked off on Tuesday with the first of four trade days to showcase the best of the Australian aviation and defence industry.
Almost 250,000 spectators are expected to come through the gates of the airport, between Melbourne and Geelong, when the biennial air show opens to the public from Friday to Sunday.
But it could face disruption as protesters plan to picket outside the airport entrance on Wednesday night and visit the nearby Lara train station on Saturday morning.
Activist group Disrupt Wars, who were part of violent rallies outside Melbourne's Land Forces weapons expo in September, has dubbed the event a "warshow".
"Harms dealers of the world will spruik their latest murder tech while smarmy politicians schmooze, slobber and sign away our tax dollars," organiser Caroline Da Silva said.
In a statement, Victoria Police said it was aware of the potential protest activities and prepared to respond swiftly to any incidents.
"We respect the right for peaceful protest however any unlawful behaviour will not be tolerated," a spokeswoman said.
Federal Defence Minister Richard Marles, who represents the Geelong seat of Corio, said he was not concerned about a repeat of the Land Forces trouble and claimed the activists were "very much a minority".
"We'll have more than a couple of hundred thousand people come through Avalon over the course of next weekend," he told reporters.
"A very small number of people (are) trying to disrupt this.
"Not by virtue of putting out there their ideas, but simply by engaging in acts of vandalism and disruption."
The federal government is bringing forward $1 billion in defence spending in Tuesday's federal budget to boost Australia's military capability.
Australia's defence spending was 1.9 per cent of its gross domestic product (GDP) in 2023, according to the Stockholm International Peace Research Institute.
UK Prime Minister Keir Starmer, French President Emmanuel Macron and presumptive German Chancellor Friedrich Merz have all flagged their intention to increase defence spending as a percentage of GDP.
It comes as US President Donald Trump's administration adopts a more isolationist foreign policy stance and pushes for a deal to end to the Russia-Ukraine war.