Attorney General George Brandis says the threat of a terror attack on Australian soil remains real, particularly with the growing trend of Australian citizens with terrorist experience gained in the Syrian civil war.
Speaking at the inaugural Interpol Global Security and Counter Terrorism Convention in Sydney on Tuesday, Senator Brandis said terrorism continued "to be a global threat of the first magnitude".
"We know that the threat of an attack here on Australian soil is real," he said.
Mr Brandis said Australia was facing a new threat from citizens who had returned home after fighting in the conflict in Syria.
"We are witnessing a growing trend of citizens travelling offshore to engage in and support terrorist activities and conflict and it has been brought home to Australia most particularly by the Syrian conflict," he said.
"These individuals are not only potentially in breach of Australian laws and commit offences offshore, but upon their return to Australia they may pose significant threats to our national security."
He said Australian fighters who returned from Syria could be "radicalised and obtain new skills", potentially including those needed to carry out an attack on Australian soil.
The three-day Interpol event is examining international policing priorities including the threat from lone terrorists, cyber terrorism, bomb technology and de-radicalisation.
Two hundred law enforcement officers from 60 countries are attending the event.
Mr Brandis said, unlike the previous Labor government, the coalition considered the threat of a terrorist attack in Australia as "undiminished".
"None of the intelligence that we are seeing suggests that the threat of terrorism is diminished," he said.
"The need to counter terrorism remains at both a national and international level one of the most important priorities for law enforcement."
AFP Commissioner Tony Negus said his agency was concerned about "lone actors who have been radicalised through the internet".
"(They're) travelling overseas to fight in other conflicts then returning to Australia with increased capability to conduct something here," he told reporters.
He said such people are "much more difficult for law enforcement to keep a handle on".
The AFP, he said, is conducting a range of investigations into people who were looking to facilitate Australians travelling to fight in Syria.