The Australian Security Intelligence Organisation (ASIO), Australia’s domestic counterintelligence service, is responsible (in coordination with the Australian Federal Police) for preventing espionage by foreign powers, and is attempting to monitor and prevent terrorist and other political violence. It is approximately equivalent to Britain’s counterintelligence service, MI5.
It is often referred to as the Australian Secret Intelligence Organisation, especially in political literature critical of the organisation, but this name has no official standing.
ASIO came to prominence in the 1950s with the Petrov affair. Throughout the 1960s, like other Western intelligence agencies it monitored the activities of Vietnam War protestors and others on the political left (some of whom were involved in espionage for the Soviet Union but many more who were not and whose monitoring amounted to little more than harassment). The distrust engendered in the Australian Labor Party led to a raid on the ASIO offices by the new Attorney-General, Lionel Murphy in 1972 when Labor won office.
The Australian Secret Intelligence Service (ASIS) is Australia’s foreign intelligence service, roughly equivalent to the British Secret Intelligence Service or the Central Intelligence Agency. However, its role is considerably more circumscribed.
It is legally banned from any paramilitary activities and there are no reports of it being involved in any. It is also not primarily responsible for the high-level analysis and reporting of the data it collects, a task performed by the Office of National Assessments.