Home Affairs boss Michael Pezzullo said the threshold for making inquiries about people's identities at airports was not keeping pace with security threats.

"It's the case that airports are regrettably a high-profile target for international terrorists," Mr Pezzullo told a Senate estimates hearing in Canberra on Monday.

"The ability to thwart a mass casualty attack in that environment has to be paramount when we're thinking about police powers."

Australian Federal Police officers can already demand people's identification at airports when they have a reasonable suspicion a serious offence may be committed.

However, Mr Pezzullo said these powers were not broad enough.

Proposed new laws outlined in the budget would allow AFP officers to check identity without cause at airports and order people to leave.

READ ALSO

"At the moment the threshold is not in keeping with best practice in terms of how to ... keep the travelling public safe," Mr Pezzullo said.

The secretary used the example of a person "casing" an airport to plan an attack to illustrate his point.

"Until you've asked the person who they are and what they're doing there, you would not have a clue," he said.

Mr Pezzullo acknowledged Australia's terror threat level had remained at "probable" since September 2014, but said it was important to keep pace with global threats.

"We've got a responsibility in departments and agencies to stay current on attack planning, the trends that we're seeing, what is happening around the world both in terms of potential strikes on airports as well as aircraft."

Mr Pezzullo took umbrage at Greens senator Nick McKim for suggesting police officers would march up to travellers and say "papers please".

"'Papers please' has a particular connotation which I am sure you are channelling to people who are interested in your views," the secretary said.

He said "Excuse me sir, can I see your ID" would be the more likely phrasing.

Senator McKim repeatedly asked what would happen to people at airports without ID, but was not given a concrete answer.

Independent senator Derryn Hinch, who supports the proposed airport powers, asked what would be done to prevent racial profiling.

Mr Pezzullo said AFP officers were expected to act at all times in an ethical, respectful and positive manner.

Former Australian Border Force commissioner Roman Quaedvlieg has questioned the need for the proposed new powers.

"I think it's largely an illogical argument to say that you need them in an airport precinct to thwart terrorist attacks but you don't need it anywhere else," he told The Saturday Paper.

Mr Quaedvlieg said along with appropriate accountability, any extra powers must be properly explained.

Australian Associated Press