LeadSled; Just have a look at the Trans Tasman Mutual Recognition Treaty section of the Australian Civil Aviation Act 1988, versus the NZ equivalent, to see how much legislative work CASA has put in, to make certain that the benefits of the TTMRA are not enjoyed by the Australian aviation sector.
To be fair, I suspect there's some in Australia outside of CASA who don't want TTMRA to work as it should and are quite happy with CASA's efforts