CAO 100.5 says what needs to be tested, when and how and how, not "if". Specific exemptions for registered aircraft will come under their relevant CAO. For example 95.10 aircraft MAY BE exempt from CAR 5 ... depending on the type of operation. Basically for 95.10 if you are more than 500 feet above your own land or over someone else's at any height and the aircraft is registered, the aircraft isn't exempt, the altimeter needs to be present and functioning accurately.
CAO 100. 5 Section 4.2
CAO 100.5 Section 4.4
CAO 20.18 says what instruments are required to operate under VFR. Aircraft registered under RA-Aus come under section 3.4 of this CAO. So firstly if your RA-Aus registered aircraft has no air speed indicator (original question was about altimeter) as required under Appendix I of the order, that would be a problem. If it was a hang glider it will most likely be operated inside a Danger "D" area and not be registered. CAR 5 section 3 part 2.3 says the air static systems is to be inspected (not calibrated) ANNUALLY for private CERTIFICATED aircraft.
CAR 5 http://www.austlii.edu.au/au/legis/cth/consol_reg/car1988263/sch5.html
CAO 100.5 https://www.legislation.gov.au/Details/F2016C00070
CAO 20.18 https://www.legislation.gov.au/Details/F2015C00342
AC 21-40(0) https://www.casa.gov.au/sites/g/files/net351/f/_assets/main/rules/1998casr/021/021c40.pdf