If you travel to Whangarei, you must visit the Whangarei Falls. I have been several times and have brought people to see this waterfall. The Hatea River takes a dive over basalt rocks creating the wide falls. There is a track from the carpark to the top of the falls, then croses the river and a steeper bit through native bush leads to the bottom of the falls, crossing the river again. If you follow the track, it leads back to the carpark. Do be careful with your car as there has been reports of cars being broken into in the carpark.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.