Australia will experience another terrorist attack "without question": expert

Another terrorist attack on Australia is inevitable, according to a White House's former counter-terrorism adviser.

David Kilcullen, an Australian who has advised Australian, American and British governments on counter-terrorism, said he was certain there will be another terrorist attack in Australia.

"We are going to get another attack without question," Kilcullen told the Herald Sun on Wednesday.

"I think it could be a cell attack and the mode of attack could be like Paris - a military assault with automatic weapons and explosives.

"More common may be someone running onto a street with an axe - the berserk behaviour from someone listening to social media that is certainly on the rise."

Kilcullen is a former Australian Army officer who was part of the Australian Defence Force dating back to 1984 who served the U.S. in various high-ranking anti-terrorism roles from 2005 to 2010.

He said that Western nations need to adopt a "continuous conflict" strategy to properly deal with terrorism, because the old ways of combatting these threats were now redundant.

"There is no going back to normal," he said on Wednesday.

"Conflict is the new normal and we need ways to handle that are sustainable and cheap enough to not break the bank.

"The traditional counter-terror approaches are not going to work anymore.

"They are not going to defeat the threat and you run the risk of turning society into a police state if you are going to actually take the actions that you would need to defeat it."

Australia has been the victim of two terrorist attacks in the last 20 years, with many other plots being foiled before they were carried out.

In December 2014, Man Haron Monis held 10 customers hostage in a Sydney cafe, resulting in three deaths including that of Monis. In October 2015, a 15-year-old boy killed an unarmed police finance worker in the Sydney suburb of Parramatta. Endit