The public servant responsible for the Department of Immigration and Border Protection has rejected claims he is trying to militarise the department.
During a Senate estimates hearing on Monday, Michael Pezzullo acknowledged the Australian Border Force had been described by commentators as a militarisation of the public service.
But the secretary of the department said the descriptions were not appropriate and it would be more accurate to say the law enforcement capabilities 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.
Mr Pezzullo said customs duties were formerly conducted by "civilian public servants" who did not have powers of arrest or powers to apply police standard investigative and operational procedures.
"Part of the modernisation we introduced under the commissioner's leadership is to professionalise that function and indeed we have a strategic relationship with the police," he said.
"All our investigative functions are overseen by a seconded assistant commissioner from the Australian Federal Police."
Mr Pezzullo said the criticism may have been prompted by the uniforms of the Australian Border Force, although uniforms had been worn by customs officers since 1901.
"In terms of the uniformed component (…) customs officers have been in uniform for I think the entirety of their history going back to 1901 as one of the founding departments of state," he said.
Mr Pezzullo and Australian Border Force Commissioner Roman Quaedvleig also apologised for the Melbourne visa-checking debacle that caused a complex police operation to be aborted, saying a press release was "factually wrong" and staff have been formally counselled.
Mr Quaedvleig also told the Senate estimates hearing the number of firearms used by the force had increased since its formation in July 2015 and would continue to increase in coming years.
"It is the intent to increase the number of officers who are able to use force up to and including lethal, however we need to go through an assessment in terms of functions," he said.
"Where we make a judgement that a function ought to be conducted by an armed officer, no person without a formal qualification will be able to take up those positions."
Mr Quaedvleig said there was no intention to provide firearms to every single member of the border force and their use would depend on operational demands.
"Anecdotally, I think the notion of officers carrying firearms is quite alien to part of the department that didn't hitherto have an exposure to that," he said.
"I wouldn't want to see ABF officers carrying firearms when there is actually no need for them to require firearms because their interface with the public does much beyond the need to use force.
"Having said that, we need to recognise that there are functions and situations that will occur in our operation environment where our officers need to be able to protect themselves and others."
Mr Quaedvleig said there was never any intention for officers to use firearms on the aborted Operation Fortitude in Melbourne.