New Zealand doesnt need to transport via air armoured vehicles or helicopters to Pacific islands with short runways. The range of a hercules with such heavy cargo makes it useless. For transporting aid in peacetime civilian aircraft can do this fine.
In terms of a medium scale conflict on the other side of the world the A330 is much more useful than a short squadron of fighter jets that some suggested here.
Troops need to be rotated, food and supplies need to be transported on standard pallets. An A330 can carry the same amount of pallets as a hercules while still carrying passengers, all while travelling twice as far and using civilian direct flight paths.
Pallets can fit in the A330 no problem.
Having A330 MRTT enter RNZAF would be fine, if and only if, other NZDF needs are met first. Amongst those needs being met first would be tactical/strategic lift.
Any A330 MRTT in RNZAF service could potentially tap into the civilian A330 support market, and/or the RAAF support (which itself is expected to draw upon some civilian support...) However, such an aircraft would be a strategic airlifter for personnel/palletized cargo. As such, it could only properly serve as a replacement for the B757's currently in RNZAF service.
In the grand scheme of things, such a purchase would make little sense, since with the exception of AAR, all the capabilities of the A330 MRTT can be fufilled by chartered Air NZ airliners if such airlift is required, without the initial and ongoing expenses associated with operating such large civilian airliners.
In order for such aircraft to operate in mid- to high-level threat environments (flying into Afghanistan for instance) a comprehensive self-defence protection suite would be required. Something which the RNZAF has already run into a problem with utilizing the B757, and such pieces of kit are expensive. The A330 aircraft, plus modifications to make it into a MRTT are expensive, and IIRC there is still a shortage of available A330 airframes given the orders booked.
Also the aircraft is big, larger than anything else the RNZAF currently operates and also requires a significantly sized runway to operate from. Given that the sort of low threat regional operations the RNZAF is likely to engage in would be various types of disasters (earthquake, eruption, civil unrest, tsunami, tropical cyclone, flooding, etc) the expectation of finding a functional runway of sufficient length to land or take off in an A330 in would be slim. Making the issue worse is that an A330 does not AFAIK have a RoRo cargo capability, while most military airlifters do have rear cargo ramps. This means that even if an A330 is able to land, it might be unable to unload any palletized cargo if cargo handling vehicles and/or equipment is damaged or otherwise unavailable. Relating to cargo, an A330 MRTT is not suited to handle outsized cargo. This often means military vehicles, which are sometimes airlifted into and out of theatres of operation. While the RNZAF is not going to be doing that constantly, simply because it lacks sufficient airlift, there are going to be times when airlifting vehicles is the best or perhaps only way to get them where needed.
Take the disaster response/recovery following the Christchurch quake. Military cargo aircraft were able to airlift engineering and emergency response vehicles in place, and could also be used to aircraft containerized hospital units, shower points, industrial power generators, etc. Unfortunately, the RNZAF would find the A330 MRTT rather unpalatable (unpalletable?) since it would be unable to airlift any of the mentioned items and other outsized cargoes.
-Cheers
