On closeup it definitely seems to have some sort of payload hanging from it, and its getting knocked around by the wind quite a bit, It doesn't appear to be falling though, just drifting west
Could be a sounding balloon to measure the upper atmosphere, meteorological folk often release them.
Poking around on the BoM website shows the met station at Perth airport released one around midday today.
https://www.bom.gov.au/fwo/aviation/IDS65024/IDS65024.94610.png
