http://www.casa.gov.au/download/act_regs/1988.pdf
166 Operating in vicinity of a non-controlled aerodrome
(2) The pilot in command of an aircraft that is being operated in the vicinity of a non-controlled aerodrome must:
(a) maintain a look-out for other aerodrome traffic to avoid collision; and
(b) ensure that the aircraft does not cause a danger to other aircraft in the vicinity of the aerodrome; and
(c) conform with, or avoid, the circuit pattern; and
(d) unless subregulation (3) or (4) applies — when approaching the aerodrome to land, join the circuit pattern for the direction in which landing is to be undertaken on the upwind, crosswind or downwind leg; and
Note A circuit pattern has upwind, cross-wind, down-wind, base and final legs.
(4) The pilot in command of an aircraft may join the circuit pattern at a non-controlled aerodrome on the base leg, for the direction in which landing is to be undertaken, only if:
(a) CASA has given approval to do so; and
(b) details of the approval have been published in AIP.
Penalty: 25 penalty units.