Glow with the flow on black-water rafting trips deep into glowworm-filled Nile River Caves (adult/child $185/150, four hours). This friendly Charleston-based operator also runs cave excursions without rafting (adult/child $120/87.50). Short on time? Take the rainforest train ride (adult/child $25/20), a 1½-hour return journey departing two or three times daily. The centre and its cafe are 26km south of Westport.

Kids aged 10 and over can raft, while the cave tours suit anyone who can walk on slippery surfaces for a couple of hours.

The Adventure Caving trip ($350, five hours) includes a 40m abseil into Te Tahi cave system, with rock squeezes, waterfalls, prehistoric fossils and trippy cave formations.