The Oparara Basin Arches are a number of natural limestone tunnels formed by the Oparara River in New Zealand. The two most famous ones are the 'Oparara Arch', large enough for a multi-storey house, and the 'Moria Gate Arch', smaller in height, but also an impressive, beautiful place (various other places in the area also have The Lord of the Rings-inspired names).
The arches can be reached by a forestry road from the main road approximately 9 km north of Karamea. The 12 km road is rough but can be accessed by normal cars most of the year. From the carpark, walks of around an hour return each are required to reach the arches. There is also a mountain bike track and a mountain lake in the area.