Many hikers consider the Dusidusky Track in Fiordland National Park to be the most challenging multi-day "Great Walk" equivalent in New Zealand. While not an official "Great Walk," this 84-kilometer trek is notorious for its rugged terrain, frequent flooding, and deep mud. It involves crossing over 20 three-wire bridges and navigating steep, untracked forest sections where the "path" is often just a series of orange markers on trees. Another contender for the "hardest" title is the Milford Track if done in extreme weather, or the Cascade Saddle route, which is a high-alpine crossing that requires significant navigational skills and is extremely dangerous in wet or icy conditions. In 2026, the Department of Conservation (DOC) strictly warns that these are not for beginners; they require high-level fitness, proper alpine gear, and an EPIRB (emergency beacon), as the weather in the Southern Alps can turn life-threatening within minutes, and help is often hours or days away by foot.