Professor Desmond Ball, of Australia National University, made the comments on ABC’s Lateline program last night.
He said the Australian Signals Directorate was sharing information with the National Security Agency (NSA) in the US.
"You can't get into the information circuits and play information warfare successfully unless you're into the communications of the higher commands in various countries in our neighbourhood," he told Lateline.
Mr Ball said Australia monitored countries in the region using listening posts.
He said there were four main facilities operating in Australia under the NSA's XKeyscore computer system, which analyses large amounts of internet data.
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They included facilities in the Northern Territory, Western Australia and the ACT.
Mr Ball's comments come after revelations that the US has been tapping into phone conversations of millions of citizens in Germany, France and Spain and the communications of world leaders.
