I'm quite interested about this NZ sighting. To the best of my knowledge, there are no shows similar to TAR which are produced locally, and in fact, the ratings for TAR have been sliding downhill since season 6, and the most recent season which aired (10), was shown in a bad timeslot.
The closest is an episode of Phil's NOW which aired last year, where 5 teams of 2 people who had never met each other raced across NZ - following closely to the TAR format, but with different terminology. It was a 48hr "challenge", and tasks were fairly limited.
If there's anything I can help with, let me know. I've lived in NZ all my life, and have traveled extensively around both the North and South islands.
Cheers,
randomnzer