Recently declassified data has shown Williamtown RAAF base has been on alert for UFOs.
The National Archive of Australia has released a file saying in June 1983, two Mirage jets were ready to engage unidentified craft flying at speeds of up to 6500 kilometres-an-hour at high altitude north of Sydney .
Subsequent analysis of radar blips determined the UFO's were generated by an interference pattern known as 'running rabbits'.
The file also shows the RAAF base has not been responsible for reporting UFO sightings since 1994, but doesn't say which agency currently undertakes the role.
