As I stated earlier, this is a topic well-addressed by economists specializing in such economies. I have every reason to believe that New Zealand can use that knowledge to navigate this hopefully short term (1-2 year) situation.
Every place in the world is suffering due to lack of tourism and there are places with more tourism than New Zealand. Yep, they'll miss some "manufactured goods."
But so will the US and UK, as we aren't going to be getting nearly as many. China is not at all thrilled about shipping to either nation. Both US and UK's trade with China is currently "constrained."
Normally, both nations could use other ports as intermediary stopping points, but that too has gotten more difficult.
The UK is going to suffer major losses as measured by GDP through this year. Whereas, I believe, New Zealand's contraction will be less. They are way more self-sufficient when pressed (being an island in the middle of the Pacific) than Wales is currently. But if UK can't use Irish and other European ports come January 1, UK will certainly feel it.
And if Mexico and Canada don't resume normal trade relationships with US, we'll feel it even more (this reopening is not going to bring back international tourism here in the US).
BTW,
Tourism is slightly less than 6% of New Zealand's economy. Not even close to being "one of their biggest industries."
Tourism in New Zealand - Wikipedia).
Farming is slightly less than tourism (only 5% of GDP). Of that percentage, less than half is for export.
They'll be fine. They are ready for this and have been active in the world conferences on how to create an economy that is not GDP-based, but has other values at its core. Also, about 20% of their trade is with Australia, which I predict will normalize and then increase.
But New Zealand has been having good internal conversation about their dropping GDP for 10 years - as it was predicted and has already been occurring. US and UK haven't had that happen yet - and we seem to be terrified of it, but there are solutions and it is not a good measure of economic health, IMO.