Immigration officials have spent more than $200,000 on hundreds of new handguns in the past three years.
The Department of Immigration and Border Protection has bought 332 Glock pistols since 2014-15, racking up a bill of $204,025.
The vast majority of its arsenal of weapons were purchased during 2015-16, the department said in reply to a Labor question in Senate estimates.
The figure has added fuel to criticism that the government was militarising what were previously civilian functions.
“This is an extension of the government’s militarisation of Australia’s quarantine and customs services,” Greens senator Nick McKim said.
“The government needs to make the public case as to why these weapons are needed.”
“They also should explain why they can spend $200,000 on weapons, but continue to deny staff a modest pay rise.”
According to figures given to Senate estimates in 2015, the Australian Border Force had 1,282 pistols, 103 shotguns, and 45 machine guns for about 5,000 officers. It is estimated border force has about twice as many armed officers as the agencies it replaced.
In comparison, New South Wales police has about 18,000 firearms for its 16,000 officers.
In 2016 the department also announced it had plans to buy stun guns for its officers.
Greens senator Sarah Hanson-Young said at the time that the arming of officers with tasers showed the “obsessive militarisation of the immigration department”.
“First they bought new uniforms and guns, then they said officers would stop and search random people in the streets and now they want tasers,” she said.
Hanson-Young said: “Border force are out of control. Will these tasers be used on everyday Australians, will they be used on people seeking asylum?”
The head of the department, Michael Pezzullo, has previously rejected claims of militarisation, instead saying that the law enforcement functions of the department had been strengthened.
“I reject completely there has been any kind of overreach that could be connoted by the notion of militarisation,” he said.
Other answers provided on notice to the Senate revealed the government has spent an extra $22m on border enforcement measures following the striking of a deal with the US government to resettle refugees.
The department also spent more than $32,000 on a five-day trip to the US by Pezzullo discuss the deal with US officials.
• Australian Associated Press contributed to this report
