I ordered a blue 256GB iPhone 17 from Harvey Norman three weeks ago. I checked today and was told it hasn't shipped yet and didn't know when I'll get it.
I don't know where other people bought theirs from, and how long the wait is. However, I cancelled my order today at Harvey Norman and got my money back. It's not worth it for a phone. I've heard some people got theirs in just a few days, but they bought from the Apple Store.

Just like every iPhone release, initial stock allocations sell out quick and you're on a waitlist for the next shipment. Even at the Apple Store direct it's a 2-3 week wait.
The black 256 GB one is readily available to pick up tomorrow at Apple Sydney, Broadway, Charleston, Highpoint, Chadstone, Doncaster, Soutland and Canberra stores among other states.
For the other colours, you may get lucky with cancelled stock at a store, but it's a wild goose chase.