They're high but not enormously so, IME if you're in Sydney or Melbourne and are competent you can be making $110k+ with 5 years experience. Even more if you're skilled in something that's in demand (data science and DevOps ATM).

From what I've seen I actually think we are lucky to have the highest dev salaries outside of the US. Which is kind of suprisingly in a way, because we don't have too many large internet companies headquartered here and the startup scene isn't huge.