I'll just add that if we had a balanced and even a slightly better funded defence force then tanks could play a part (although the question could be, what type eg heavy or medium? Then some other questions if heavy, would we be better basing them in Australia, to enable quicker and efficient deployment to where they would be needed? And as a real and genuine contribution to "the defence of Australia"? After all if Aust is ever "over run", then NZ will be too. Always best to fight your enemy away from your own shores if possible and contribute to collective defence etc).
In the meantime until the correct funding is found I would suggest it is not a high priority (NZDF overall - there would be other higher priorities), and as NM nicely articulates it would require additional funding to build up "engineering, mechanical and logistics support". (Which is not impossible to overcome but it would be done over time. If we look back at the introduction of the LAVIII the Army needed to vastly upskill, technically, over a many years. So the skillsets are much better now, probably not quite there for "tanks" but could be further built upon).
However ... and this may seem contradictory - I also don't believe the status quo is the correct path looking and moving forward, and some "corrections" need to be prioritised right now.
1. The Army has always required better mobile/protected fire power than 25mm (the LAVII turret). If we put "tanks" aside for a moment, what other mobile/protected options would be suitable for NZ with at least 76mm or 105mm caliber (and then should they be wheeled or tracked etc)? Remember the Army only lost its 76mm firepower with the early retirement of the Scorpions and the later decision to acquire additional LAVIII's (to equip two motorised battalions, rather than less LAV's and new additional Fire Support Vehicles).
2. The Army needs to train in working with tank formations (ideally).
3. But IMO this is also important and needs to be addressed. When overseas military forces comes to NZ for training, in essence they come to a place here that is like tailored for light infantry and firepower. Not that I am an expert but to me this seems rather "unrealistic" in terms of what modern threats need countering, when training. If this is an issue I would advocate that the NZDF obtain a small number of heavy (or medium) tanks, such as say 10-12 for example, which could based within the North Island (Waiouru) designated training area (and perhaps some in the South Island (Tekapo) training area). Perhaps logistically/support wise this might not be practical, but I was trying to avoid the need to deploy them from Linton (NI) or Burham (SI) chewing up roads and possibly restricted by old bridge infrastructure?
This would be a relatively "cheap" proposal.
Being "training aids" it would be easier to "sell" the concept to both politicians and the inevitable anti-defence critics we have, after all who can deny the need for the NZDF to train for the "modern" battlefield? They are also not intended to be deployable (which would be another issue altogther, logistics and support wise). Perhaps also they wouldn't need all the "bells and whistles" (in terms of counter measures etc) hence saving costs (but on the other hand the more "bells and whistles" the more realistic the training. Will leave that to the experts, the Army themselves to decide). But I'm sure the US would be willing to sell (or lease) some tanks to NZ even if they were not necessarily at the latest standard, at affordable prices.
If this happened, we would have a small (training) nucleus that could also in time, should the strategic environment require it, allow NZ to acquire and build up a capable and deployable armoured force element (and the training and sustaining etc), should the funding be prioritised for such.
Something similar could be done in terms of an initial fast-air training capability, but that's another issue altogther (and would be a lot more costly).