It's 5.8% of GDP, 20.4% of exports. [0]

That's a large figure, but it's not as if New Zealand lacks any kind of other industry. There's a massive primary industries (dairy, meat, logging, wine, plus others) where the country hasn't yet fully exploited it's opportunities yet for secondary value-add processing.

As a completely anecdotal observation, most tourists go to the South Island, where roughly a fifth of the population lives. The North Island is four times as densely populated. This disparity sometimes leads people to believe that country is entirely dependant on tourism, with a few sheep thrown in.

[0] https://tia.org.nz/about-the-industry/quick-facts-and-figure...