The old RMB 90 tax in China was Airport Construction Tax - used to build and maintain airports. And its not just for international passengers, it was for all air passengers, from RMB50 tp RMB90 depends on the distance you fly.

The New Zealand one is nothing to do with any airport - if you stayed more than 24 hours, you have to pay a $25 New Zealand Departure Tax, collected by Bank of New Zealand for their government before you allowed to leave that country. And it is only targetting international passengers. Total nonsence.

http://www.newzealand.com/travel/tra...y-facts.cfm#10