As has already been mentioned, the checking and verifying that INZ does for a Partnership resident visa application is much more thorough and in-depth than for a work visa application (think potential phone calls, interviews....at the very extreme, a visit to your home by INZ - but this only tends to happen in very rare cases where there are serious concerns about the genuiness of the relationship). And the volume of evidence provided should be more significant than with a work visa application.

As an LIA based in NZ (Tauranga), I have about 30% of my clients still based overseas (communications via email and Skype when necessary), 50% in various other regions of NZ and only about 20% of my clients are actually local in Tauranga. Sometimes it's nice to put a face to the name who is helping with such a huge life matter, but with most of the business of immigration done online these days, it's not necessary to be in the same city as your adviser/lawyer.