I think australia is hampered by the law, which may make any kind of no males or no females requirement illegal, it has to be demonstrated necessary and possibly this is only acceptable on a case by case basis for sport?
According to this article, you absolutely can discriminate on the basis of sex:
Australian 1984 Sex Discrimination Act (Part II, Div. 4: 42 – Sport): ‘(1) Nothing in Division 1 or 2 renders it unlawful to discriminate on the ground of sex, gender identity or intersex status by excluding persons from participation in any competitive sporting activity in which the strength, stamina or physique of competitors is relevant.’