Cloudee, the Part 91 MOS states:
“26.43 Supplemental oxygen
(1) An aircraft operated at a pressure altitude above 10 000 ft (a relevant aircraft) must be fitted with supplemental oxygen equipment capable of storing and dispensing supplemental oxygen to crew members and passengers.”
Here is a link:
https://www.legislation.gov.au/Detai...t#_Toc57289557