Feminism theory states that "men and women should be equal politically, economically and socially" ("Feminist Theory: Examining Branches of Feminism," sascwr.org). We can easily see feminism theory playing a role in the film Australia, especially through the actions of the character Lady Sarah Ashley.
In the beginning of the film, when Lady Ashley decides that her husband's cattle station, Faraway Downs, must be sold, she determines that she must travel to Australia, sell it, and bring her husband back to England all herself. She makes this decision contrary to her financial adviser's opinion, as we see in the earlier scene. Her decisions are a portrayal of feminism because she asserts herself as being socially and economically equal to her husband. Not only that, she makes this decision in the face of what appear to be insurmountable odds as Australia was considered a very wild terrain. We even see some feminist symbolism in this scene as Lady Ashley jumps her horse over a wall while saying the emphatic word "myself."
We further see feminism theory being portrayed when Lady Ashley arrives in Australia and is treated as a source of intrigue by the Administrator as he rightly sees her arrival as a means of breaking Carney's monopoly over the cattle industry for the military. However, we also see Lady Ashley acting contrary to feminism when she arrives in Australia with all of her fine clothing and unmentionables from England, which are quickly ruined. By not properly equipping herself for the harsh environment of the Outback, she portrays herself as far softer than she really is and is treated like a joke by both Drover and the manager of Faraway Downs, Mr. Fletcher. However, the destruction of her belongings due to Drover's bar fight symbolizes her letting go of her softer side. It takes her some time, but she soon presents herself as being as tough as Drover. She even decides to help drove the cattle to Darwin. She needs some training from Drover, but proves herself more than capable, which is another portrayal of feminism theory.
Multiracial identity theory, or mixed race theory analyzes the "experiences and consequences associated" with individuals that have a multiracial background (Shih, "Toward understanding multiracial identity"). These experiences and consequences can easily be seen in the film Australia surrounding the mixed race character, Nullah, as well as other mixed aboriginal children. Nullah felt that he had a mixed identity. He felt drawn to learning about his aboriginal identity from his grandfather, as we can see from both the opening scenes and the scene in which he leaves Lady Ashley to "go on walk-about." However, he also felt drawn to his white background and began to see Lady Ashley as a mother figure. We can see their connection in the scene in which he "sings" Lady Ashley to him from the boat after Missionary Island was bombed. Of course the consequences of his mixed identity can be seen in the British treatment of mixed aboriginal children.