AHC New Zealand a pacific powerhouse by the 20th century

If relations with Australia were not amicable then NZ would have to become a powerhouse to defend itself.
 
They'd broaden their immigration prorgammes at an early stage, like Australia did after WW2 to undertake the 'populate or perish ' policy.
 
With what population base?

They'd broaden their immigration prorgammes at an early stage, like Australia did after WW2 to undertake the 'populate or perish ' policy.

New Zealand is currently a net exporter of food (one of the largest per capita, actually, in terms of value, though much of that is meat and dairy, so it's relatively expensive), so it could probably support a much larger population. That said, most arable land is currently under the plow, though they could do some fruit trees and livestock in some of the hilly-but-not-mountainous regions. If most of the new population was in highly concentrated urban regions, or up in the agriculturally unproductive mountains, they could probably support a higher population. With intensive agriculture and food imports, maybe even bigger than Australia's current population, but...

What does "power" mean? It'll never be more populous than Japan or Indonesia (or China). I'm not even sure I'd say that Australia is a Pacific power today.
 
Like with most Western nations in the sourthern hemisphere the one and only way to make them considerably more influential than OTL is to greatly nerf the rest of the world. So your bog standard nuclear war that also knocks out Australia will do the trick, cue major immigration from Australia to NZ and challenge accomplished. There are probably some much cleverer ways to do this, but ultimately the relative resource bases means that something needs tonne holding back the OTL major states.
 
How do you rate Israeli power, out of interest

GDP about 35th in the world compared to NZ on about 53rd, the worlds 5th largest air force, large high-tech manufacturing sector with significant exports, space programme, nuclear weapons with independent launch capability, independent alliance network, significant efforts toward self sufficiency in resources. All of that sort of thing.
 
GDP about 35th in the world compared to NZ on about 53rd, the worlds 5th largest air force, large high-tech manufacturing sector with significant exports, space programme, nuclear weapons with independent launch capability, independent alliance network, significant efforts toward self sufficiency in resources. All of that sort of thing.

Not trying to derail the thread, but... Israel has the 5th largest Air Force? Sh*t, that's impressive. The comparison is rather illustrative.

Now, back to the OP, does having New Zealand in some kind of "union" or federation with mainland Australia counts (and Australia being the "junior partner" for some reason)? Perhaps both Australia and NZ are integrated into the same colonial administration for some reason, and then Australia despite its enormous size suffers some issues that allow the transplantation of the center of decisionmaking to NZ... that's far-fetched, I know (much like having the UK administered from Ireland or the Austrian Empire from Romania), but let's try to keep an open mind, considering its an AHC.

Let's say, for example, that settling in Australia is less interesting than in NZ (indeed, we can compare the ratio of available land in the whole of Australia, with but New South Wales and the western tip having bigger population centers), and somehow even these more settled regions in Australia suffer widespread depopulation and migration towards NZ (just to work with an example, an even more aggressive Japanese attack, but now we might be slipping to a "Man in the High Castle" setting, I admit). In due time, with the correct administrative and economic developments, NZ might become a Switzerland or Nordic country of sorts in the Pacific zone, and with a more sizeable investment in modern weaponry, which dispenses huge manpower (such as a Navy), it might become a formidable power.
 
Honestly, it would probably have to be more of a Maori empire, with having one group conquer the rest and then instigate some kind of colonial program. British New Zealand is just going to be too depopulated to become a true great power.
 
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