Airport security ratchets up after raids disrupt 'plot to blow up plane'

Security has been increased at Australian airports after police foiled "Islamic-inspired" plans for a bomb attack on an aircraft during counter-terrorism raids in which four men were arrested on Saturday, the Australian Federal Police confirmed.

"The travelling public can expect to experience an increased level of security scrutiny at the airport but they should not be concerned about these precautionary measures", it said.

Travellers flying on domestic flights were warned by carriers including Qantas to arrive at airports at least two hours before their scheduled domestic flight and three hours for worldwide flights.

Passengers should arrive at the airport two hours before domestic flights and three hours before global flights to allow ample time for screening.

Travellers have already experienced delays at airports due to the added security measures.

Keenan said while he can't go into specific details about the investigation, Australia's security agencies were constantly working to ensure public safety.

The beefed-up security has also caused crowds to congregate in baggage claim areas, as additional screening of checked-in luggage came into effect. "[Increased security measures] will be required for as long as the threat is assessed as requiring them". The additional time will be allotted for additional security screening to prevent terror acts.

Colvin said the plotters had been intending to use an "improvised device" to bring down a plane, although he wouldn't elaborate on what type of device it was.

Sydney Airport has put on extra staff to manage the delays.

Khaled Merhi, Abdul Merhi, Khaled Khayat and Mahmoud Khayat are being held in custody but are yet to be charged over the suspected bomb plot, as police continue to comb their Surrey Hills residence for evidence.

"We face a range of terrorist threats", Turnbull told reporters.

"This is an example of the outstanding work that is conducted by the joint-counter terrorism team", Turnbull said in remarks broadcast by Australia's ABC News and posted on his official Twitter account.

Flying back into Brisbane from Sydney on Sunday morning with her two daughters, Elyse Wallace said she faced long queues while departing, but was happy to arrive home on time.

"But it will be take more time".

  • Eleanor Harrison