From CASA website
NOTE: Some airports are classed as security controlled but do not have RPT operations. An ASIC is not required at these airports.
Essendon and Moorabbin airports have an area for RPT operations that is designated as security controlled and an ASIC is required. The remainder of the airport is not security controlled and an ASIC is not required. If you have any queries regarding whether or not an ASIC is required at a particular airport, or in a specific area of a particular airport, you should contact the airport direct or contact the Department of Infrastructure, Transport, Regional Development and Local Government.
ASIC is not required at Archerfield