It is not an Airservices issue but CASA, related to MOS 139.
139.030 Aerodromes with non-precision approach runways to be
certified or registered
(1) A person must not operate an aerodrome to which subregulation (3)
applies if the aerodrome is not a certified aerodrome or a registered
aerodrome.
Penalty: 10 penalty units.
(2) An offence against subregulation (1) is an offence of strict liability.
(3) This subregulation applies to an aerodrome that:
(a) is available for public use; and
(b) has a non-precision approach runway.
And yes, it is to do with the owners of certified and registered aerodromes being required to have a monitoring system in place, unlike lower aerodrome categories.
Subpart 139.E Obstacles and hazards
139.350 Monitoring of airspace
(1) The operator of a certified aerodrome or a registered aerodrome must
monitor the airspace around the aerodrome for infringement of the
obstacle limitation surfaces by:
(a) any object, building or structure; or
(b) any gaseous efflux having a velocity exceeding 4.3 metres per
second.
(2) The monitoring must be in accordance with the standards set out in
the Manual of Standards.
Further info, agenda item 5.6:
http://www.casa.gov.au/wcmswr/_asset.../vic100422.pdf