Discussion on this has been a regular forum and aus.bushwalking subject for many years and there has never been a definite legal answer because (A) legislation differs from state to state (B) legislation changes over time (that
malenyvoice item in the last post is now out of date - for something more recent see
https://www.claytonutz.com/knowledge/2010/may/-water-boundaries-in-queensland-the-new-rules-from-may-2010) (C) differences due to when the land title was established.
In other words for the non-legal citizen it's a legal morass and any advice found could easily be wrong and/or out of date unless you get professional and competent legal advice.
Then after all that there is the prospect of encountering unhappy land owners who don't accept your well-researched legal argument.
The answer I would recommend:
(A) FInd the contact number of the occupier of the land you want to cross, usually by contacting the local NPSR ranger station.
(B) Ring occupier, identify yourself, provide your phone no. for possible future need, tell them what you want to do and on what date and ask for permission to cross. If permission not given, thank them for their time and hang up.
I have followed that procedure for many years and had very few knockbacks (two if memory serves me and they had polite reasons). There have been times the occupier has asked for help (finding lost cattle) when walking/climbing to places the occupier seldom goes. Another time coming down from Mt. Mistake the occupier (never met before) had tea, coffee and cake laid out waiting for us all as we neared the house.