That is one of the major sticking points about QF taking a cornerstone investment in ANZ.
There are several consequences.
If QF takes the shareholding, and ANZ moves into Oneworld, then it is almost definite that the Star Alliance will start it's own Australian East Coast / Trans Tasman operation.
ANZ has to look at whether it is prepared to lose the traffic feed from the USA it gets it from UA and several other US carriers who do not want to align with QF/AA, in return for a partial feed of Australian traffic - expect QF however to not let too much of this go to ANZ.
There are then the implications for Freedom (makes you wonder why ANZ would ramp up a budget carrier right in the same territory as QF's new budget operation, Australian).
Perhaps Freedom will be the "patsy" - sold off as an "independent" operator to ensure that competition trans-tasman meets the regulatory restraints expected by both the Australian and NZ Competition authorities.
Last but not least, expect a severe back-lash by the members of the ANZ Airpoints scheme who like the flexibility that Star provides, as well as the product. Sadly, Oneworld just does not seem to have the same interchangeability in product, particularly when QF largely mirrors NZ's prime destinations. Never underestimate the power of the populace to exert influence in both the boardroom, and on the majority shareholder!!