In parallel with his academic and public service careers, Dibb worked for the Australian Security Intelligence Organisation (ASIO) to gather counterintelligence on the Soviet Union capabilities in Australia for over 20 years from 1965 to 1984 [REF].
Confidential documents show that in 1977, the Central Intelligence Agency believed Dibb was a more valuable informant for the CIA on the Soviets in Canberra than was ASIO itself.