Be interesting to see what a future hypothetical RNZAF @ Whenuapai could look like.
If we were to have something based on the RNZAF up to the mid-1990's, then Whenuapai is short of one tactical airlift squadron (1 Sqn Andovers). So
if such a sqn were to be resurrected in the future, would that be sufficient to fill up the base? In addition to the present Sqn's of course (C130's, P3's and Navy Seasprites).
Although perhaps an alternative option, if the funding were to be found somehow, is to follow the RAAF direction, which would be in our case a strategic airlift sqn consisting of the 757's plus either 4-6 A400's (or one or two C17's). Then you could have a tactical 4-5 C130 Sqn for those South Pacific type operations (rather than have Andover type replacements eg C27, CN295 or Q400 etc). Thinking about this more lately we would get more versatility from C130's rather than an Andover type (plus the benefits of 4 engines over water etc) as long as we had a larger airlifter in the next decade to move the Army etc.
Otherwise an additional sqn or detachment of 2-4 NH90's or A109's (or something in between these two types) should be based at Whenuapai regardless for counter-terrorism, SAR and regional civil defence emergency use etc.
And there's that coastal air patrol option also.
Finally, if the day ever came whereby NZ regained an Air Combat Force, perhaps a detachment of 2-4 aircraft should be based there for CAP over NZ's largest city and economic powerhouse etc (post 9/11 etc). At least the people of Auckland would get to see that their ACF is "doing something practical" ... (and queue propaganda newsreel) and is "protecting its citizens" etc.
Even if were a detachment of MB339's from Ohakea if they get reinstated (for now, until/if something better comes along etc). The MB339's machine guns would be sufficient as they will only ever encounter unarmed aircraft around these parts etc (it's unlikey a hostile fighter would ever make here of course, not unless someone nicks off with a warbird jet and somehow managed to fit a live firing gun but that's unlikely too)! Apart from a hijacked aircraft threat, the other credible threat could be a "terrorist" armed with a high-powered rifle/MG/RPG firing out of a helicopter etc. However the MB339 doesn't have air-air radar so it would have to rely on upgraded ground based primary radar if there were a need to intercept etc (for example when the ACF was disbanded back in 2001, a year or two later a joint civil/military primary radar site near Ohakea was shut down and I understand we rely mainly on secondary radar nowadays. But in a post 9/11 world I don't believe that is sensible, if indeed this is the case). If this sounds far fetched, wasn't there some recent news report about NZ police or a new armed unit being formed to be "armed air marshals" on some Air NZ flights??? [Edit: here's the media report
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10548656 ]
In terms of joint Army basing, again follow the Aussies and get a better air defence regiment/SAM system in place. They can be based there but are intended to be deployed overseas to support NZDF and coalition ops etc (not so much as airfield defence battery for Whenuapai itself etc). We need something more than a Very Low Level Air Defence system (Mistral) etc.