Heavily armed police will block off and patrol sections of Sydney ahead of the ASEAN summit while, behind the scenes, security forces have developed myriad tactics to prevent extremists from harming the harbour city.
Prime Minister Malcolm Turnbull will host Southeast Asian leaders on Saturday and Sunday for a special summit to discuss regional security, economic ties and counter-terrorism measures.
NSW Police Minister Troy Grant has proposed beefed-up police powers which allow police to block-off parts of the city, conduct searches, remove vehicles which are causing obstructions and prevent drone flights.
"The security of this summit and the dignitaries visiting from neighbouring nations is of paramount importance and these measures empower police to do what is necessary to help ensure the safety of everyone involved," he said in a statement on Tuesday.
Armed police, traffic controls and guarded perimeters are now part of the "rhythm of daily life" in the age of lone-wolves and vehicular attacks, counter-terrorism experts have told AAP.
"Experience in the Middle East and elsewhere shows that drones and the use of cars as weapons are now the new normal," Australian National University Professor John Blaxland said on Tuesday.
Leaders expected to come include Indonesian President Joko Widodo, Myanmar defacto leader Aung San Suu Kyi, Malaysian Prime Minister Najib Razak, Singaporean Prime Minister Lee Hsien Loong and Thai Prime Minister Prayut Chan-o-cha.
The high-profile and contentious leaders gathering at ASEAN make it a target for disruption by those who oppose policies and figures in Southeast Asia, according to Prof Blaxland who heads up the ANU's Strategic and Defence Studies Centre.
He said many of ASEAN members understand terrorism operates in the "twilight zones between states".
"Notably in places like the Sulu Sea abutting Malaysia, Indonesia and the Philippines.
"These countries have come to recognise the overwhelming benefits that accrue from greater regional cooperation."
Prof Blaxland and Deakin University counter-terrorism expert Greg Barton agree high visibility policing serves an important role in deterring potential attacks.
"Sometimes the best way to deal with people (security forces) are worried about is simple - uniformed police or a marked car parked outside their residence sends a signal not to try anything rash," Prof Barton told AAP on Tuesday.
"But much more is covert."
The movements and communications "chatter" of high-risk groups and actors are likely to be monitored in the lead-up to major gatherings including ASEAN, Prof Barton said.
Police "incident response" teams, armed with military-style weapons under new NSW legislation, will be on standby in case surveillance misses a threat and the worst occurs.
Critical to their success, Prof Barton added, would be the lessons learned during the city's first taste of modern terrorism - the Lindt Cafe siege.
"It was all new to us then," he said.
"Police learned lessons, they'll respond differently, much quicker, more decisively if something happens at ASEAN."
Police are now able to shoot-to-kill if an immediate threat emerges, he said.
"Ugly things can happen and perhaps the lesser of two evils is shooting to kill."
Mr Grant did not provide details as to where the police will be focusing their efforts, although it's understood it would include the harbourside suburb of Kirribilli, where the prime minister often hosts events at Kirribilli House.
The police minister said the laws were waiting for final approval and would be introduced on Wednesday.
© AAP 2018