The argument posted by Midfielder has been done to death before by many of local (Aust) fans who can't count. The argument is based on the fact that FFA allows a NZ based team while styming the local growth.
This is of course nonsense. FFA did not agree for the NSW South Coast team, and more significantly, the Canberra team, to join the league recently, and this was on the business model - basically they were unlikely to thrive long term without financial support of the federation.
Wellington Phoenix does not take a "space" away from these franchises. It lives and dies on its own income or lack of it, so it only helps the league by providing additional team to play in the comp, while requiring no funding from the FFA. All other jingoistic reasons aside, it is a win-win for both countries. The moment Australia has a league big enough to provide long meaningful season, this topic could be revisited. At the moment, it is a non-issue. And I say that as an Aust citizen living in Christchurch.