Not too sure, although I think logic would dictate that NZers and politicians would prefer to be able to not have to onward travel from a port inland. Sure, once planes are a thing, that is different, but that postdates federation.
It may be possible to review the correspondence/speeches of the time from NZ politicians like Stout, to see if they expressed a preference.
I've been scanning through links without success so far, but here is an interesting summary of various points or positions
http://www.gedmartin.net/index.php?id=152&option=com_content&task=view
That's an interesting link; I'll have to read it tomorrow though. I hate to think of the size of the documents you go through which make this seem a 'summary'