I have just been dropped in the back of whoop-whoop. I'm at the airstrip at Mitchell Falls, an X-shaped scar carved from scrub close to the Kimberley coast of Western Australia, and it's lonely.

Kununurra is 330km in one direction, Broome 530km in the other. The closest capital city is Dili in Timor. I came here in a chartered Cessna from Kununurra and I'm waiting for a helicopter that will take me out to the good ship True North for a cruise along the Kimberley coastline.

All the other passengers boarded at Broome, the vessel's home port, but I'm on board only for the five-day cruise east from here to Wyndham.

The strip here is used only occasionally by miners and since the plane disappeared I'm all alone. It's well into the dry season and I drank the last of my water half an hour ago. I wonder if I've been forgotten for about the fifth time when there's a whop-whop-whop and the cavalry arrives in the form of a white Bell Jet Ranger which appears above the trees and lands in a maelstrom of dust.

On board is Craig Howson, owner of the vessel, the pilot and a couple of passengers along for the ride. I pile on board and we head out to the vessel, with a fly-by of Mitchell Falls on the way. It's truly wondrous, a succession of four falls with blue pools cradled by red sandstone gorges in between. You'd be happy to have it as your screensaver, but the real wonder is yet to come.

"Let's take a look at some art," says Craig. We land beside a small waterhole, climb a sandstone outcrop and deep in the shadow of an overhang is a frieze of about a dozen elongated figures painted in dark red ochre on the wall with elaborate headpieces and decorations on their arms and ankles.

They're captured in wafting motion and executed with finesse with a fine brush - Giacomettis translated to a rock wall. These are Bradshaw figures, one of the great enigmas of Kimberley art.

Scattered across an area of 50 000km2, Bradshaw figures might be 60 000 years old, and they seem to have separate cultural origins from the main corpus of Aboriginal artwork. Exactly who painted the Bradshaws we might never know, but they suggest a society of style and sophistication - which increases their appeal. But they're only one facet of this extraordinary place.

The Kimberley defies description. A wild, arid plateau at the northern end of Western Australia almost twice the size of Victoria and home to just 30 000 people, the Kimberley sucks the breath from your lungs and leaves you panting, a place where full-blooded adjectives fall silent faced with the enormity of the task before them.

Parched semi-desert for the most part, the Kimberley is guttered by a handful of snaking river systems that swell to galloping furies in the wet season, then trickle to nothingness in the dry. Its icon is the baobab tree, an African immigrant that looks like a Coke bottle mated with a sea anemone. Road trips in the Kimberley involve heat, dust and a bed somewhere in the dust.

The view from the waterline, on the other hand, is the cool, calm way to go, and True North is one of several expeditionary-type vessels that ply the coast between Broome and either Wyndham or Darwin from April to September.

A couple of minutes after take-off from the art site we're over the milk-blue waters of Admiralty Gulf and bumping down on the top deck of the True North. It's obvious that this is the sybarites expeditionary vessel. In service since the beginning of 2005, the sleek, all-white, 50-metre 36-passenger True North lifts Kimberley cruising to a new level of luxury. There are also some unusual rules. Don't hang your arms over the side when fishing or a croc might think they're cocktail sausages. Also, crocs sometimes haul out on the transom during the night, so that's a no-go area.

No sooner have I installed myself in my quarters, bounced on the bed and fiddled with my personal DVD player than a fishing trip is announced.

Fishing for me usually involves mayhem and blood - mostly mine - so rather than inflict my piscatorial incompetence on my fellow passengers I opt for the sightseeing variation. For an hour we go charging across the bay in one of True North's tinnies, wind in our hair, sun on our hides and spray whizzing from our bow.

It's glorious, but the combination of heat, lack of nourishment, a pre-dawn start from Darwin and several bouncy plane rides have taken their toll. With what I consider to be a fluid and unobtrusive movement I grab for the side and gently retch.

By dinnertime I'm back in top form, and it's just as well. From the galley come a series of culinary wonders, tastefully arranged in a way that would do credit to a food fetishists' magazine.

The next morning, we're at Rocky Cove in Vansittart Bay, 120km closer to Wyndham from Admiralty Gulf, and Craig has arranged a picnic for us. It's no ordinary picnic. As well as costumes and towels it involves a helicopter and a secret destination, and here a word about Craig Howson is essential. Large, affable and supremely contented with the world, he has been operating cruise vessels along the Kimberley coast for the past two decades.

Imagine you're aged about 10 and you've got a dad who knows everything about fishing and boats, has his own personal chopper, can put on a killer barbecue and make sure there's a well-chilled, age-appropriate beverage to hand. Adventure and fun at every turn in other words - and that's Craig.

It's a 10-minute flight from the ship to a place that Craig has christened Eagle Falls, where a boisterous river steps down from the escarpment to the plain below in a series of waterfalls with rock pools in between.

Each pool is clear, cool, edged with pandanus palms and perfect for swimming. The best is at the top, a deep pool perhaps 100m across, at the foot of a staircase of blackened sandstone steps iced with foaming water. Although there are several vessels that cruise the Kimberley coast, only passengers on the True North will ever see this. The river is too shallow even for small craft, and without a helicopter, you'd never know it existed. By the time we've splashed and swum and jumped off the falls and quaffed a glass of sauvignon blanc the crew have prepared a feast of scallops seared in the shell, giant prawns, fish streamed in foil, salads and fruit.

Next morning we're at King George Falls, the mid-point of my cruise, 'km north-west of Wyndham and one of the highlights of the Kimberley. Once clear of the sandbar we enter a narrowing gorge with 50-metre rock walls closing on either side. Everyone is out on deck, cooing, clicking and squinting at the viewfinder of brand new video cameras in a way that promises to test the bonds of kinship at their next family video evening. It's dramatic in a grandiose way, the rock stacks teetering out from the main wall, waiting for the moment when they will finally topple into the water.

After cruising for about an hour upriver we round a final bend and the river widens at the amphitheatre of King George Falls. It's like Venice - we've seen the pictures, we know what to expect - but even so, King George Falls comes as a surprise.

As it reaches the edge of the escarpment the river splits into two, creating twin cascades separated by a knobbly sandstone outcrop. In the dry season the flow will cease to a trickle or even stop completely but right now it's thundering, tons of water exploding at the base, sending a plume of spray high into the air.

There's another cruise vessel and a yacht at anchor in the deep water off the falls, and once again we discover the advantages of an on-board chopper. Instead of the hot slog along the path to the top of the falls, we take the elevator - a 30-second ride. At the top of the escarpment the river pours through a series of broad and surprisingly placid waterholes en route to the precipice, and we loll and splash like contented hippos.

It's the last night of the cruise, time for the traditional True North Mad Hatters Party Night - fancy dress required. An op-shop's worth of scarves, hats, wigs, is scattered across the dining room tables and we're invited to create our fantasy character.

After dinner, certificates are handed out for the various ways in which we have distinguished ourselves. Everyone gets a prize. There's the most prolific angler, the lobster award for the most impressive case of sunburn, the intrepid photographer award for continuing to film while passing though a waterfall. As well as the podium, it's also a moment for ritual humiliation.

I get the commendation for most improved sailor. The story of my unwell episode over the side of the tinny is related in unnecessary detail.

The morning after we're berthed at Wyndham, deep in the broad notch of Cambridge Gulf. Wyndham's port, which once shipped Kimberley cattle to Asia, barely functions these days, but even so this town of 850 feels like another world.

There's a bus waiting to take us to Kununurra and we're strangely subdued at the developments that this presents. For the first time since I boarded I put on shoes instead of sandals and they feel tighter than they did, a little strange. It's going to take some getting used to.

If you go...

• VISAS: South African passport holders need a visa to enter Australia.
• Getting there: Quantas and SAA fly daily to Australia or you can travel with one of the Far East airlines and make a connection to north western Australia.
• INFORMATION: For more information and bookings aboard True North, contact Northstar Cruises so check out their websites: www.northstarcruises.com.au