Screening at Australian airports has intensified and travellers should expect delays after authorities foiled a terrorist plot to bring down an aircraft using an improvised device.
Travellers have been warned to arrive two hours earlier because of "additional scrutiny" and security experts say the arrangements will likely be in place for the foreseeable future.
"What people can expect to see is an increased police and security agency presence," Federal Police Commissioner Andrew Colvin said in Sydney on Sunday.
"You can expect longer delays to make sure that more screening is being done on baggage - both hold luggage as well as hand luggage."
The measures began at Sydney Airport on Thursday before being extended across Australia.
Dr John Coyne, who heads the Australian Strategic Policy Institute's Border Security Program, said the immediate counter measures to eliminate threats would give authorities the chance to analyse potential vulnerabilities.
Passengers might notice more precise x-ray screenings or an increase in swab tests, but there could also be more personnel behind the scenes monitoring anomalous behaviour, he said.
"The question will be how were these guys allegedly planning to get this device onto a plane," Dr Coyne told said on Sunday.
"Is there an actual vulnerability they were going to exploit, and is it something we need to mitigate.
"That will be the big question that will be faced now and over the coming weeks."
On Saturday afternoon, NSW and Federal Police swooped on five properties in the Sydney suburbs of Surry Hills, Lakemba, Wiley Park and Punchbowl and arrested four men.
Mr Colvin said terrorists were becoming "ingenious" about coming up with ways to bypass security, but he was also confident Australian security procedures would have stopped the plan.
Dr Coyne agreed and said constant reviews and input from international experts kept travellers safe.
"I don't mean to sound flippant, but you're still safer travelling by plane anywhere in the world - even with the current counter terror threat - than you are driving on Australian roads, if you're talking about statistical probability of getting hurt or killed."
Mr Colvin said there was no reason to believe the integrity of airport security had been compromised.
The terrorism threat level in Australia was raised to "probable" in 2014.
Since that time, terror incidents overseas have involved everyday items including vehicles being used as weapons.
But in a submission to a Senate committee examining aviation security, the Australian Security Intelligence Organisation (ASIO) noted "civilian aviation will remain a high-value terrorist target for the foreseeable future".
Terrorists were "adapting to security measures already in place and subsequently changing and refining their methods", the committee's report said.