The outgoing spy boss wants the Australian public to become better prepared to defend the nation, saying his agency has "seeded" awareness of a growing threat posed by foreign interference.
ASIO director-general Duncan Lewis said Australia's middle power status made it a target for state-sponsored cyber attack, and described covert attempts to shape public opinion as a daily event.
Mr Lewis, speaking at the Lowy Institute in Sydney on Wednesday, said foreign interference against Australia was on a "growth path" and combined with espionage posed a potential existential threat to the nation.
He said he was pleased public discussion in Australia of foreign interference and espionage had grown and created more awareness, and warned the damage from these threats could manifest following a delay.
"Covert attempts to influence and shape the views of the public, media, government and diaspora communities, both within Australia and overseas, is now with us every day," he said.
"Unlike the immediacy of terrorism incidents, the harm from acts of espionage may not present for years, even decades, after the activity has occurred.
"These sorts of activities are typically quiet and insidious, with a long tail."
Foreign interference had emerged as a front page issue reported by media in the five years since he became ASIO chief, Mr Lewis said.
"There has been a great deal of coverage recently in the Australian media regarding espionage and foreign interference, ascribing blame and describing vectors of attack and influence," he said.
"It is not proper for me to dive into the detail of this coverage for a number of reasons, suffice it to say I am satisfied that ASIO is following the ball closely and has seeded what is now a public consciousness and awareness of the matter and I hope in short-order there will come an increased public preparedness to better defend our country and its sovereignty."
Foreign interference was "something that is still on a growth trajectory" after the emergence of technology and globalised networks, Mr Lewis said.
"Communities and countries are able to interfere in one another's business now, because you can."
Mr Lewis also warned there was a "flip side" to growing public discussion of foreign interference and urged against vilification of minorities in response to the actions of a few.
"We had this experience when it came to the Islamic community and terrorism, and we saw some terrible discussions taking place a few years ago where vilification of a demographic was taking place, when we, ASIO, were only interested in a few," he said.
The long-serving public servant, who will depart his role this month after a 47-year military and civilian career across government agencies, repeated his warning that the terrorism threat had plateaued but remained unacceptably high.
He warned ISIL's loss of territory in Iraq and Syria did not eliminate the global threat of Islamic extremism.
"Indeed even in their former claimed territories the extremist ideology of their cult remains," Mr Lewis said of ISIL.
"Increasingly, disillusioned ISIL supporters are turning to more egregious and desperate measures in and beyond the Middle East."
ASIO was also paying attention to the threat of right-wing or ethno-supremacist extremism, he said.
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"Recent history around the world is peppered by acts of extreme right-wing motivated attack.
"The event in Christchurch is a horrific example of an anti-social loner with perverse sensibilities and no regard for community or diversity who felt obliged to conduct an act of extreme violence and brutality."
Mr Lewis named foreign espionage alongside terrorism and cybersecurity as one of three "threat vectors" to have ASIO's attention.
He repeated his previous warning that the scale and scope of espionage against Australian interests was unprecedented, but said the nation's response to the threat had been strengthened through new legislation targeting foreign interference and improving transparency around foreign influence.
"This threat is not confined to any one particular nation; however you can appreciate the intent, scale, sophistication and commitment varies greatly."