The Oparara Basin in one of the finest features of the Kahurangi National Park. For a million years the Oparara River system has been at work sculpting the 35 million-year-old limestone basin into an intriguing complex of caves, arches and channels.
The forest is a mixture of beech and podocarp, thickly carpeted with mosses and ferns growing in shallow moist soil and squeezing root systems through cracks to gain a hold.
Unique ferns and algae live around the arches and cave entrances.
Birds, insects and fish flourish in the environment, which is also home to the rare short tailed bat, the giant land snail, the cave spider and whio/blue duck. The Oparara Basin is a great spotted kiwi sanctuary.
All insects, fossils, native birds and plant species are protected. Underground cave formations can take thousands of years to grow just one centimetre. They are fragile creations - even the oil on your hands can damage formations.
The basin is about 20 km north of Karamea.
An old forestry road provides access for walkers, cavers and other nature lovers to the Oparara Basin. The road branches inland approximately eleven kilometres north of Karamea on the road to Kohaihai.
It is a further 12 km to the arches car park and another three kilometres to the caves car park.
This gravel road is narrow and steep in places and can become corrugated especially after prolonged dry weather. Take care, keep your speed down, drive with lights on and be prepared to stop or pull over.
The road is not recommended for campervans and a height restriction bar of 2.8m will be installed to restrict access to larger campervans by the end of January 2018.
There are some shuttle options available out of Karamea, contact the Karamea Information Centre for details.
Safety is your responsibility. Wear sturdy footwear and suitable clothing. Drive to the conditions - keep your speed down on the gravel road, have your headlights on and be prepared to pull over for other road users.