Jim Eagles (NZ Herald)

I am crawling on my elbows and knees up an icy stream which flows through a long narrow cave about half a metre high. The torch is waterproof – but my shirt, trousers and boots are definitely not.

The stony stream bed is hard on the knees and elbows and at times the cave is so narrow I have to squeeze between the unyielding rocky sides.

But then the tunnel opens into a huge cave. A galaxy of glow-worms twinkles from the roof high above. And all around, my torch beam picks out glistening white pillars, exquisite shawls which glow golden in the torchlight and long, delicate clusters of straws made from limestone.

Cold, wet feet and scraped knees are suddenly forgotten. This is an adventure with a treasure trove of beautiful limestone formations as the prize. And I’m a winner.

What makes the privately owned Nikau Cave, in the Waikaretu Valley, about an hour-and-a-half southwest of Auckland, so special is the fact that it is still in a natural state.

There are no concrete paths, no handrails and no electric lights. The only concessions to visitors are some steps dug into the earth down to the entrance and a wooden ladder at the exit. Otherwise you walk up the stream bed or clamber over rocks shaken loose by past earth tremors. The only lighting comes from torches. There are certainly no handrails and if you try to steady yourself by making a grab for a handy stalagmite you’ll cop a shout of “don’t touch” from guide-owner Philip Woodward.

So it’s easy to imagine the 1km long cavern has only just been discovered and you are among the first to explore its magical depths.

In fact, the cave was known to Maori and early settlers in the district, and it was mapped by the Auckland Speleological Society about 50 years ago, though it has never been widely publicised.

Woodward, who has lived in the Waikaretu Valley all his life, remembers going through it once when he was a teenager and marvelling at the experience.

But when he and wife Anne bought the land 28 years ago, he says “the presence of the cave wasn’t a factor in deciding to buy and it certainly had no impact on the price”.

It was only when farming conditions got a bit tough 11 years ago they decided to diversify into tourism and take people on tours of the cave, as well as offer farmstays and scenic walks.

However, the number of visitors is still small – last year the total reached 1700 – and the Woodwards limit group sizes so as to not affect the peaceful, untouched atmosphere of the cave.

Even getting to Waikaretu Valley is like a journey back to a quieter, gentler time.

Turn off the Waikato Expressway and cross the Waikato River at Mercer and you’re in rural New Zealand as it was before lifestyle blocks, huge mock-Tudor farmhouses, painted rail fences, alpacas and macadamia trees transformed the landscape. Best of all there’s no traffic, so you can meander slowly along, enjoying the rolling countryside, patches of beautiful bush, bouncing spring lambs, herds of horses, flocks of turkeys, warbling magpies and amazing numbers of hovering hawks, without the risk of a sparkling clean four- wheel-drive shoving its bullbars 10cm from your towbar.

The official directions to Nikau Caves involve turning down the Waikaretu Valley Rd soon after Glen Murray, but we were feeling adventurous so we drove past the intersection and kept going.

This led us to Waingaro Hot Springs, where a swim would have been nice if only we’d brought our togs, and a cold handle of Waikato would have been even nicer, but the sign on the door of the Waingaro Hotel said it was closed for renovations, so we kept on to Raglan.

Raglan is still an attractive town, even though it has been discovered, and we had a pleasant stroll along the beach and some terrific corn fritters with bacon at the Salt Rock Cafe before continuing the expedition.

Still feeling adventurous we left the main highway and took the Te Akau Coast Rd and enjoyed another peaceful drive through green valleys, which sweep down to bays where the the west coast waves smash into the shore, past verdant fields which are gradually being eaten up by the inland march of the sand dunes, around spectacular limestone formations and pancake rocks which look like the crumbling palaces of some ancient civilisation, and on to the strangest sight of all, a giant windturbine sitting motionless on a hilltop, looking like an invader from another planet. It is a stark reminder of the $23 million flop of Vortec Energy back in 2001.

From here the coast road heads to Port Waikato and the bridge across the Waikato River at Tuakau, the route we’ll take on our way home, past more amazing rock formations, including the spot where Peter Jackson filmed Weathertop Hollow for Lord of the Rings and – good heavens – a flock of peacocks shimmers in the sun.

But the turbine marks the bottom of the Waikaretu Valley, so we turn inland to Whare Matoro where the Woodwards offer a relaxed variant of farmstay, with delicious meals in front of a roaring puriri fire – venison stew with tamarillo pie to follow – and peaceful accommodation.

For many years they have progressively fenced off and covenanted areas of the farm and there are some beautiful walks through the bush. One goes to the top of the farm where, on a clear day, you can see the snow-capped cone of Taranaki, another weaves along a stream bank to a delightful waterfall overlooking the remains of an old sawmill.

But the highlight is the cave visit. The biggest caverns, the far side of the crawl, are beautiful.

A sweep of the torch around the walls and ceilings picks out an amazing array of chandeliers, shawls, pillars, terraces and sculptures built up over the ages by the steady drip of limestone-saturated water.

Turn off the torch and the hundreds of glow-worms on the ceiling turn the darkness into a glowing replica of a starry night.

My description of getting there might sound a bit scary and it is a bit of a test of nerve which, Philip agrees, is not for everyone. “On one occasion, of a party of 11 only three actually made it through the tight bit.”

On the other hand most people enjoy the challenge. “The oldest I’ve taken through is 93 and the youngest is 2, ” he adds, “so it’s not too tough.”

If confined spaces are a worry, you can always see most of the best formations by going in through the exit. But you’ll miss out on a great experience and the satisfaction of having overcome a few phobias, plus the certificate of achievement issued to those who make it.

Among the most regular customers are groups of at-risk teenagers who come precisely because there is a challenge to be overcome. “For some, the experience has literally been life-changing,” says Philip. “I’ve also had people here weeping at the beauty of the cave. That sort of thing is pretty rewarding.”

If most people do survive the crawl through the narrow tunnel it’s probably because Philip’s calm competence and sense of humour make it hard to feel nervous.

Just before we climbed feet-first through a narrow cleft and slid on our backs 3m down a sloping rock into the cramped, dark, wet entrance to the tunnel he asked if we’d remembered to bring our snorkels because the stream level was up and the first section was underwater.

At one stage he used to carry a large plastic spider which he would leave around for people to find. “I had to give that up after it gave a woman hysterics.”

And he has fooled a lot of people – including travel editors and Department of Conservation officials – with his story that the holes in a mud bank near the cave exit are caused by kiwis digging for insects . But behind the jokes is an obvious love for his patch of land. “We don’t do this for the money,” he says. “It’s because this is such a beautiful spot and we want to share it with others.”