If you want a cheap flight from Auckland to Tokyo, you've got two airlines to choose from.
You can use the filters on your search to see more flights and find cheaper rates – Tokyo has more than one airport. So if you don't need to fly into Tokyo Haneda International Airport, it's worth checking your other options. The 8848 km flight usually takes about 35 hrs 45 mins.
There are about ten flights to or via Tokyo every week, so you have plenty of options.
If you're planning on going to Tokyo during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.