Koutu Boulders are near Kauwhare Point in the Hokianga Harbour, Northland. They are the same kind of spherical concretions as at Moeraki Beach in Otago and Whitecliffs on the Rangitikei River in Manawatu. Some of the boulders are the largest of their kind in NZ.
Access to the boulders is not well-signposted, but they are easy to get to once you know the location. From State Highway 12, northeast of Opononi, take either end of Koutu Loop Rd, then turn onto Waione Road. The car park is immediately on your left and may be unmarked. From the car park, walk to the beach and head north a few hundred metres until you see the first boulders. There is a good collection, with boulders in varying states. You can continue to the Kauwhare Point to see the biggest ones. Access to the point is once the tide is far enough out.