Away from the lush green landscapes and untouched beaches that dominate New Zealand's tourism campaigns is a barren, inhospitable island.

What draws visitors to White Island (Whakaari) in boatloads is a fascination with the bizarre and desolate - a morphing, gushing landscape that has claimed lives and forms a counterpoint to postcards of idyllic paradise.

It is New Zealand's only active marine volcano, 49km from Whakatane's coast. Whakaari's private owners allow access to a group of helicopter companies, fixed-wing aircraft and a single boat company.

Despite being warned of seasickness, I take the boat option, which is a six-hour round trip with a 90-minute tour of the inner crater.

Thankfully, the promised spectacle of boat crew rushing around with sick bags does not eventuate. The voyage over a slow, rolling swell is eased by the cushioned interior - no bus seats here - and a powerful ferry that churns along at a good pace.

After 1 hours the volcano emerges from the mist. The only signs of life are ash-tinged pohutakawa that skirt the outside of the crater, and grey-faced petrel that flit between the branches.

Sharks are known to bask in the sun in the shallow bays. A local charter fisherman recently complained that his kingfish were being torn off his lines by bronze whalers.

Even the entry to the island is unwelcoming - a sinking jetty of cracked concrete and jagged iron bars. The sight of this alone has convinced some tourists to remain on the boat.

When a blustering southeasterly makes it difficult to moor the boat to the jetty, the crew make precarious landings in a boulder-filled bay nearby.

Once I am standing within the crater the volcano has an apocalyptic feel. Cracks in the surface belch steam, so hot and dense it was used by Maori to cook petrel (before they sold the island, reportedly, for two barrels of rum).

Sheer cliffs, some nearly 300m high, plunge down into a crater lake filled with a lurid green bubbly broth.

The only human mark on the crater is the rusted and collapsed carcass of a sulphur factory.

The building replaced another factory on the same site that was pushed out into the sea by an enormous landslip, killing 10 miners.

On approaching a vent, which roars like a jet engine, the skin on my legs tingles and the back of my throat becomes irritable.

"That's the sulphur," says our tour guide. "Catches in your throat, doesn't it?"

I slip on my gas mask, and take a careful walk between boulders, finding delicate sulphur crystals, streaks of acidic, yellowed rock and mud pools.

The tour guides have an unmistakable New Zealandness about them. They are barefooted while at sea, affable, and most of them pull a double act as guides and sailors.

As we head back to the boat, a guide offers me the chance to swim in one of the bays of the island.

With bemused tourists looking on, I plunge in headlong. Diving downwards, I find sediment from the crater turns the water a gorgeous, glowing turquoise.

The disappointment of not seeing any dolphins or whales on the trip over is forgotten. I bask in the light swell, warmed by the hearth of the volcano, until a crew member, grinning, reminds me of the sharks.

The boat is full on the Tuesday that we visit, and an afternoon tour has also reached its capacity of 60.

Permits have been given to only four tourist operators so that the island is not overrun and its terrain damaged.

George Raymond Buttle bought the island in 1936 not only because he "rather liked the idea of owning a volcano" but also because of its "unbelievable beauty".

White Island won't find its way into a 100 per cent Pure New Zealand campaign, but the beauty is in the oddity of the place, a journey to the end of the world yet only a boat ride away in the Bay of Plenty.

* Getting there

White Island Tours (0800-733- 529; six-hour trip including lunch $175).

Accommodation: White Island Rendezvous (0800 242 299)

The boat tour company has 25 rooms above its reception and cafe, so if you're weary from your volcano visit you only have to cross the road from the harbour to rest or jump into the spa. The studios are immaculate and spacious and have large balconies. Peejay's Coffee House, which is also within the building, serves great creamy coffee, ideal for a pre-voyage wake-up.

Food: The Wharf Shed (07 308 5698)

Fresh fish travels just metres from the wharf to the kitchen, so it is no surprise that seafood dominates the menu at the Wharf Shed. The restaurant is also a regular award-winner for its lamb and beef, and vegetarian and sushi meals are available. The presentation for my main is unusual - lamb stuffed inside a brioche - but delicious. There is also a White Island-themed dessert, with meringue, icecream, cream and yoghurt. On warm evenings you can dine on the wharf overlooking the estuary. Booking is recommended. Two courses with wine, as well as a superb locally brewed Mata beer, cost me $75.