Spectacular Rustgill - Tumblr Posts
Looks like a Spectacular Rustgill or Gymnopilus junonius. They often grow on tree stumps and tree bases.
This species also occurs in Southwest and Southeast Australia.

In the picture I cannot see the gills, I am assuming it has gills because it looks exactly like a Spectacular Rustgill, so they might still be covered by the cortina (veil).
I also found a picture of a person who identified a Spectacular Rustgill in Australia which looked really similar.


So shortly, I am fairly sure it is a Spectacular Rustgill or Gymnopilus junonius.
I hope this helps:)
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I got the pictures from iNaturalist:

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@writingraccoon Hiyaaa:) The op being Australian does help so thanks for letting me know. I do not mind being tagged in identification posts, I like id'ing fungi:)

looka this mushroom from my backyard