Spy chief Mike Burgess says up to four countries, including Iran, are actively involved in foreign interference in Australia.
"I can think of at least three or four (countries) that are we've actually actively found involved in foreign interference in Australia and diaspora communities, and some of them would surprise us," the Australian Security Intelligence Organisation's director-general told ABC Insiders on Sunday.
Mr Burgess added: "When we find (foreign interference), we deal with it effectively."
Foreign interference and espionage were key security concerns for the national intelligence and security agency, with a range of countries, including Iran, caught attempting to threaten and intimidate diaspora communities.
Iran was able to be identified publicly because the federal minister had already done so, Mr Burgess said.
Earlier this year, former cyber security minster Clare O'Neil revealed ASIO had disrupted the activities of individuals conducting surveillance in the home of an Iranian-Australian.
Revealing identities of other nations engaged in foreign interference was a decision tor the new Home Affairs Minister Tony Burke, Mr Burgess said.
The spy chief's foreign interference remarks follow Republican US presidential candidate Donald Trump's campaign accusing the Iranian government of hacking its internal communications, though Reuters was yet to verify the identity and the motivation of the alleged hacker.
Mr Burgess also used the public appearance to urge politicians and the media to be careful of their language following the decision to raise the terrorism threat level.
The threat level was raised from "possible" to "probable" last week due an increased risk of politically motivated violence.
Mr Burgess said the upgrade was driven by "a broad range of ideologies", with more people being radicalised quickly and "more people thinking violence is the answer".
Young people were particularly vulnerable, the ASIO chief said, with five of the eight incidents of acted, planned or alleged acts of terrorism investigated since April involving minors.
Tackling the problem required society-wide involvement, with families, community leaders, governments and the media all having a role to play.
"The media has to be careful about their headlines, it can inflame," he said.
"Politicians have to be careful about their robust political debate," he went on, stressing that was a general message for all politicians and not targeted at any individual or party.
