Ms.Norris, Australian passport holders don't need a visa to Hong Kong for up to 90 days, she just needs to apply for a single entry visa to Mainland China, the fee is 40 Australian dollars. You can apply for it in late May or early June. generally speaking, the single entry visa is valid for 3 months, if you apply for it too early, it will expire, otherwise, you don't have enough time to apply for visa.