Domestic intelligence agency ASIO says it has not been able to keep up with the growing level of "harmful espionage and foreign interference" operations being carried out in Australia, which have sought to steal sensitive government and corporate information and covertly influence public debate.

The secretive agency said it had struggled to meet the demands of confronting two major threats, terrorism that "shows no sign of diminishing" and an "unprecedented" level of hostile foreign interference that was "expanding in its scope and complexity".

"Foreign intelligence services sought access to privileged and/or classified information on Australia's alliances and partnerships, our position on international diplomatic, economic and military issues, our energy and mineral resources, and our innovations in science and technology," director-general Duncan Lewis wrote in ASIO's annual report.

On top of these operations, the spy agency "identified foreign powers clandestinely seeking to shape the opinions of members of the Australian public, media organisations and government officials in order to advance their country's own political objectives".