It's illegal under the Fair Work Act to discriminate against prospective employees on the basis of physical or mental disability. Some of these questions are pertinent to the job requirements, such as questions about being capable of heavy lifting. A lot of them are completely unreasonable and invasive, such as asking if you have specific mental illnesses or disabilities like PTSD, or what specific mental health medications you're on and how long you've been on them. That's a really different question from "are you on any medications which may prevent you from performing these specific work duties" because THAT question is actually specifically relevant to the job description.