Oceania is a bit of a peculiar case when it comes to listing the monarchies. If you want to find out about the Queen of Australia or New Zealand, you better check out the British pages: Queen Elizabeth II is the Head of State of no less than 16 states.
The Māori kingdom is another special case. The Māori are the indiginous people of New Zealand, having come from East Polynesia. They have their own monarch, who mostly has a ceremonial role and acts as the unifying personality of the Māori minority in the country, so the Māori King is not a sovereign Head of State. Find out all about it by clicking the flags!