Sawcut Gorge and the mysterious area known as “The Zoo” had been on my tramping list for years. Following the 2016 Kaikōura earthquakes, this spectacular corner of the Seaward Kaikōura Range was closed for a long time.
However, after spotting a track update in the Permolat group mentioning volunteer maintenance, followed by a Wilderness Magazine article pointing out topographical map inaccuracies regarding the permanent closure of Isolation Hut and Zoo Hut, we knew it was time. With a stellar weather forecast for the east coast of the South Island, we booked our flights for an adventure into the Isolated Hill Scenic Reserve.
Fast Facts
- Location: Isolated Hill Scenic Reserve, Marlborough, New Zealand
- Topo50 Map: BS 28 Kekerengu
- Direction: Clockwise to Isolation Hut first as it is much easier to go down the Waimā River especially with the deeper pools
- Difficulty: Moderate due to unmaintained track, boulder hopping
- Start / Finish: Ure Road. Park approx 4km back from the end of the road (opposite the area marked “Kilgram” on the map)
- Huts: Isolation Hut (6 bunks), Zoo Hut (4 bunks)
- DoC Warnings: Zoo Hut toilet has damage and is not safe to use (July 2026); Travel through Sawcut Gorge is not recommended due to risk of rockfall & track is no longer maintained – enter at own risk (July 2026)
- Best Season: Summer, due to it being warmer for river travel and lower flow levels
- Dogs: Yes, with DoC permits only
- Other Kaikōura Tramping Trips: Te Ao Whekere, Jam Hut, Mt Tarahaka
Our Trip Overview
| Section | Time (hr) | Elevation Gained (m) | Distance (km) |
| Ure Road Carpark → Isolation Hut | 3 – 4 | 261 | 8.7 |
| Isolation Hut → Zoo Hut | 6 – 7 | 1,093 | 10 |
| Zoo Hut → Brian Boru Biv | 2.5 – 3 | 250 | 10 |
| Brian Boru Biv → Ure Road (via Brian Boru Stream & Waimā River) | 6 – 7 | 110 | 13.5 |
⚠️ FAQ: Critical Route Warnings
Yes. Older topographic maps contain inaccuracies that show the huts as permanently closed—a hangover from the Kaikōura earthquakes when officials closed all huts in the wider area. However, visitors should note a current DOC alert for Zoo Hut: the floorboards in the toilet have completely rotted through and are collapsing into the pit. Go prepared to bury your waste.
DOC staff use these huts for biodiversity work. While the department does not intend them for public use, they leave the doors unlocked.
No. There is a locked gate on Ure Road preventing vehicle access to the road end due to private land. You must park approximately 4 km back from the end of the road (opposite the area marked “Kilgram” on the map). From the parking area, you must walk up the Waimā Riverbed to access Blue Mountain Station.
Zoo Hut sits on a narrow sliver of public conservation land surrounded by private land on three sides, including the nearby Zoo swamp.
The section past the Napoleon Biv junction and climb out of Brian Boru Biv towards Zoo Hut is rough, overgrown, and less frequented. Treefall can obscure track markers and be hard to spot at times. Allow extra time. Closer to Zoo Hut, the DOC track sidles along a private property fence line where there are no markers. For this stretch, simply follow the fence line to stay on course.
⚠️ FAQ: Critical Safety Warnings
Yes, the track through Sawcut Gorge to Isolation Hut and Zoo Hut is not officially closed but the Department of Conservation (DOC) does not actively recommend access & there is still a sign at the road end stating the Gorge is closed. The area was heavily impacted by the 2016 Kaikōura earthquakes. While volunteer groups maintain the route, walkers enter at their own risk due to ongoing cliffside instability, active slips, and rockfall hazards. You need to stay alert at all times.
Rockfall: Active slips and unstable cliffs mean you must remain highly alert and avoid stopping inside the narrow gorge sections.
Flash Flooding: Sawcut Gorge, Brian Boru Gorge, and Waimā Gorge are narrow slot canyons. In heavy rain, water levels rise rapidly with no escape routes. Do not attempt this tramp with rain forecasted.
Freezing Water: The gorges receive very little sunlight and stays incredibly cold. Pack plenty of warm clothes. It is best as a summer trip.
No swims are required in Sawcut Gorge but they are completely unavoidable in Waimā Gorge. There are no high sidle tracks available because the steep gorge walls drop straight into the water. Expect approximately 6 deep pools that require you to be a confident swimmer. You will need your gear in a packliner & dry bags. However, travelling down the Waimā Gorge is not required as you can simply walk back out via Sawcut Gorge rather than making it a loop.
Day 1: Ure Road to Isolation Hut via Sawcut Gorge
The ‘Warm-up Gorge’
The 4 km riverbed tramp up the Waimā River offered a gentle start. Tony and I enjoyed lunch watching curious alpacas on the hillsides above and spotting beautiful kōwhai trees. Arriving near Blue Mountain Station, we were amazed by the numbers of rare black pīwakawaka (fantails) fluttering around us.
Past Headache Stream, we hit what we termed the “Gorge Warm-Up”—a narrow section with a high sidle track equipped with ropes for the steeper traverses and descents back to the river. After scrambling over large boulders on the true right of the river, we crossed into DOC conservation land and a DoC warning sign about no stopping in the gorge due to rock fall.
The Spectacular Sawcut Gorge
Entering Isolation Creek, the landscape dramatically changes as you enter Sawcut Gorge. This spectacular limestone slot canyon towers over 150 meters high while narrowing to just 2 to 4 meters wide. It completely dwarfs you. Seeing how these perfectly smooth, intricately patterned rock faces survived the 2016 Kaikōura earthquakes is absolutely awe-inspiring. It reminds you how amazing nature is.
Further up Isolation Creek, strong wafts of sulfur that at first made us think of geothermal processes like what can be found in Lewis Pass with hot pools like Hot Spring Stream in the Hope Valley. However, once home, Tony consulted his geological map and found that the strong smell of sulfur is due to the type of rock in the area. The geology of Isolated Hill Scenic Reserve is amazingly complicated with many faults including the Clarence Fault. One of the many strata is ‘argillaceous limestone.’ This limestone contains iron sulphides and organic matter. These rocks erode and release hydrogen sulphide gas (rotten egg smell). And, strangely human noses can smell hydrogen sulphide in incredibly small amounts (less than 1 part per billion). The smell is real but is a geological illusion. It’s simply the natural weathering of the rock rather than geothermal hot springs.
Eventually, the gorge widened into a beautiful basin. Isolation Hut sits nestled here in the mānuka below Isolated Hill. We spent a cozy evening cutting firewood, toasting marshmallows, and eating fresh pasta and garlic bread by a roaring fire. At night, the bare limestone peaks above looked as though they were capped in snow.
Day 2: Isolation Hut to Zoo Hut via Napoleon Biv Junction
We awoke to a crunchy frost outside Isolation Hut. It was June after all. There was no time for a slow warm-up; we started with a steep 400-meter climb toward the Napoleon Biv junction. The bush was alive with the calls of tūī and bellbirds (korimako). Despite high goat numbers in the area, regular DOC culling has started to minimise their damage and there was healthy undergrowth including young tōtara. What I enjoyed most was the beautiful bark of the giant matai trees, it’s dimpled and different shades of brown providing a fascinating pattern on the bark of the trees.
Past the Napoleon Biv junction, the route became noticeably rougher and less frequented, requiring navigation around treefall before a steep, loose scree descent to Brian Boru Biv.
Looking for exotic animals in The Zoo
The first kilometer from the biv toward Zoo Hut proved slow and frustrating. The track was heavily overgrown with scrub, and we lost the markers multiple times—including one instance where a fallen tree had spun a marker completely upside down and sent us in the wrong direction before realising our mistake. Knowing we’d finish in the dark, we pushed on.
Fortunately, the track vastly improved once we hit the top of the climb and began sidling through beech forest before we climbed out of a creek to a surprising private property fenceline. The DOC track edges right along this boundary line, meaning markers disappear for this stretch on the margin of private land. Navigation is simple: just follow the fence. We made swift progress, joking that the fence, once electrical, was designed to keep the exotic “Zoo” animals and birds contained and stop them wandering off private land and onto conservation land. At one point, the fence was strung high above a gully. Tony joked this was to keep the Zoo’s birds inside.
As darkness descended, we had 1km left still to the hut. Tony sent me ahead to get the fire started. I told him to be careful as night time would be when all the Zoo animals would be waking up. By the time Tony arrived at Zoo Hut I had a roaring fire going, and the hut had already starting to warm up.
Day 3: Zoo Hut to Brian Boru Biv
We opted for a relaxed 1:00 PM departure from Zoo Hut, spending the morning playing Bananagrams by the fire and soaking in daylight views across to the striking Chalk Range.
The return journey to Brian Boru Biv was significantly easier. Because Brian Boru is so compact, it stayed warm enough overnight despite lacking a woodburner.
Day 4: Pack-Floating the Waimā Gorge to Ure Road
Our final day followed the Brian Boru Stream down into a magnificent gorge environment again. The first 1.5 km was straightforward, but once we hit the confluence of Box Stream and transitioned into the Waimā River, the water volume increased drastically.
Faced with deep pools, with no possibility of sidling due to high gorge walls, we inflated our packraft, stashed our heavy packs inside, jumped on top of them and used a walking pole to paddle across. At one pool, I accidentally pushed Tony in the raft away before jumping on, resulting in a freezing, gasping swim for me through the deep water!
In total, expect around 6 deep pools in Waimā Gorge where swimming or pack-floating is completely unavoidable because the steep gorge walls drop straight into the water. Waimā Gorge is arguably even more spectacular than Sawcut Gorge, featuring a stunning 100-meter waterfall dropping off the top of the gorge walls.
The gorge finally opens up about 2 km before the Isolation Creek confluence. From there, it’s a fairly straightforward rock-hop across large boulders at times back to familiar ground and Blue Mountain Station.
Trip completed June 2026