The next day, while waiting for my bus to arrive, I decided that instead of sitting around twiddling my thumbs I'd put them to some more practical use - so I dropped into the nearby indoor climbing centre. Without a friend to counterbalance me, I was confined to climbing in the Cave - a room whose walls and ceiling are covered in brightly coloured handles of all sizes and whose floor is thick with rubber padding. As I was sweating and gritting my teeth trying to make it along the bottom of a simple vertical surface, 10 year-old kids skipped over the walls and ceiling, seemingly oblivious to gravity's persuasive arguments.

Next I spent two spectacularly sunny days idling in Wanganui, which upon reflection was a foolish thing to do. However, I only realised this as the bus approached New Plymouth. This western coastal town is dominated by the conical volcanic peak of Mount Taranaki, or at least it is when the weather is good. As we drew closer, the dark silhouette of Taranaki disappeared behind a thick layer of cloud. By the time I jumped from the coach it was raining. The situation got progressively worse. It was June and winter had arrived. I and my fellow hostel residents gave up our plans to climb to the top, so we turned to New Plymouth's other attractions, one of which is, yep, a climbing wall.

Hitching a lift with fellow hosteller, Austrian occupational therapist and belay counterweight, Roswhita, I attempted to outdo the 10 year-olds. I spent a lot of time hanging above the ground staring at the walls wondering how on earth anyone could expect someone without 10 foot limbs to reach all the necessary hand and footholds simultaneously. Needless to say, Roswhita sped up the walls almost as fast as the kids. After four days we finally gave up all shreds of hope and I bad Roshwita and her 25-year old red Triumph farewell and boarded the bus to Otorohanga.

The rain was still driving against the windscreen of the taxi from Otorohanga to the tiny hamlet of Waitomo, and my confident assertion that the weather couldn't affect Waitomo's particular brand of attraction began to crumble with every successive thunderclap. So, there I was, dangling off a rope again, this time looking down at the brown rain-swollen river a hundred feet below me. I began to question the wisdom of this expedition. Waitomo sits on a giant slab of limestone that is riddled with subterranean rivers and caves. Simon, our guide, seemed to consider the situation "borderline", but was prepared to "give it a go". He seemed supremely competent, which boosted my confidence, but also slightly mad, which did not.

First we had to get to the river, which lay at the bottom of this 100 foot chasm. My previous abseiling experiences have always been against a solid rock face, which at least gives you the reassuring - if incorrect - impression that you are still standing on solid ground. There was no rockface this time. I descended, spiderlike, into the depths - dripping greenery giving way to a twilight world of twisted and fractured limestone. My feet landed squarely in the shallow river with hardly a bump. Our party of three squelched off along the riverbed, our headlamps glinting off the muddy-brown water.

The river was mostly shallow, but in parts it was so deep and fast flowing that it was hard to keep moving forward. Matters weren't helped in this respect by the large inflated tractor tyre innertubes we were carrying over our shoulders. These were to be our mode of return transport. We explored quiet caves away from the rushing turmoil of the main river. Caves deep in wet clay that sucked at our boots beneath the silty waters. We forged ahead to a quieter backwater and rested on a clay and pebble bank. Extinguishing our headlamps we waited for our eyes to adjust. Slowly the small blue-green pinpoints appeared. Thousands of glow worms shimmering on the cave ceiling. We watched in silence, until Simon unexpectedly let off a small explosive he'd brought with him. As the noise ricocheted around the cavern the glow worms brightened, reflecting off the waters below and providing enough light to allow us to see our hands in front of our faces.

The return journey was a lot quicker. Jumping onto our innertubes we glided along, carried by the current, this time being able to appreciate the limestone architecture painstakingly assembled over several millennia. Returning to our open chasm we had to climb back to the fading light of the real world. The 100 foot climb was surprisingly easy - perhaps all that practice had paid off - although exhaustion was setting in.

The next day it rained again, and all the subterranean tours were cancelled - for once I had been lucky with the weather. After a brief stop in the city of Hamilton I'm back in Auckland once more, now sitting in an inexpensive but stylish café eating the best vegan chocolate cake I've ever tasted. Much more civilised.