Some of the larger recruitment firms gather data about the market. Hays publishes an IT Salary guide, their latest FY 23-24 doc was created in May:
https://www.hays.com.au/documents/276732/1102429/Hays+Salary...
In the prior year's general guide for the entire AU/NZ job market - not just IT - Hays said the labour market was the tightest they'd ever seen in half a century, on the back of covid-related border restrictions to immigration.
Re: the salaries listed for roles salary guide, they might be representative of median offers, but there's also a tail of situations and niches where a specific project in a business is willing to offer 2x or 3x the median salary to the right employee/contractor at the right time. Although granted, maybe that's based on what the market was like 12 months ago.
I suspect the Australian IT job market & salaries are bi- or tri- modal. Small local businesses don't have enough scale in their business operations and aren't in a position to bid as high for engineering salaries offered by the large non-tech domestic employers such as the big banks. Then our large domestic employers compete against each other for engineering talent, but aren't necessarily willing to bid against well funded US companies that have engineering offices or are willing to hire remote in Australia.