The track starts with a gentle 10 minute climb, through a number of rocky outcrops and over-hangs. It then follows an undulating ridge, branching off at different points, to allow exploration of the various caves in the area. There is a lookout point along the ridge that has a clear view of the stratified layers of rock comprising the "intact block" of rock that slid down from the Ngamoko Range.
At one point the track takes two different routes (marked "track" and "bypass"). The track takes you down through a rock tunnel several metres long and the bypass takes you around a large, jutting rock over-hang.
The track then descends into a small valley that contains the largest number of caves on the walk. It is worth spending a little time exploring them with a torch, although care must be taken.
Cave weta are found in the Onepoto Caves. These harmless insects gather in the caves during the day and venture out at night to feed on plants.
From the valley, the track climbs back up to a narrow ridge. Part-way along the ridge there is a second lookout point that gives good views of the lake and Panekire Bluff to the west. From this point you can see back over the valley to the ridge you originally climbed, and to the first lookout opposite.
From this lookout the track continues (very close to SH 38), eventually emerging near a small car park and lookout of the edge of the lake. You can either return back along the caves track, or walk back along the road.
The Onepoto Caves Track is situated close to State Highway 38, approximately 10 km south of the Aniwaniwa Visitor Centre. The track is a 2 km long return trip and is signposted at the road side, at the site of the original lake outlet. The end point or turning point of the track is a lookout and parking place above the edge of the lake, right next to State Highway 38.
Most of the original forest around Onepoto has been affected by fires until recent decades and along the track you will see relatively young broadleaved forest, with small pockets of older, black beech trees clinging to dryer sites on rocky outcrops.
The Onepoto Caves were formed by the same upheaval that created Lake Waikaremoana some 2,200 years ago.
The Waikaretaheke River used to flow through a deep, narrow gorge between the Panekire and Ngamoko Ranges. It was dammed by a huge landslide from the Ngamoko side of the gorge, probably triggered by an earthquake. The landslide blocked the river with debris over 300 metres thick, spilling up and down the valley for 3 km.
A second landslide of similar size, also from the Ngamoko Range, slid down to join the first and settled in an almost intact block on top of the earlier debris.
The Onepoto Caves that you see today were formed in this "intact block" of strong, layered sandstone as it fractured and bent under the stresses of sliding and the subsequent impact. In many places you can see the "jigsaw" effect of interlocking rock shapes with caves and tunnels forming narrow slots between them.
The Onepoto Caves range from small cavities and rock over-hangs, to deep recesses and tunnels up to 20 metres long, some with multiple entrances.
The Onepoto Caves (also known as Te Ana-o-Tawa Caves) were well known to the Maori people of the Lake Waikaremoana area. Oral history tells of Tuwai, a warrior chief of Ngati Ruapani, who slew five men who tried to overcome him while he slept in one of the caves.
Another story tells of the time that Tuwai and some of his people took refuge from a Kahungunu taua (war party) in Te Ana-o-Tawa. Tuwai, placing himself at the narrow entrance to the cave, disposed of the enemy one by one as they tried to enter.
It is essential to take a torch if you intend to explore the caves as they have little natural light ad some of them contain hazards such as deep holes and slippery floors. Children should be accompanied by an adult.