Blood, tears and sweat

I'm dripping with sweat. The group has fallen silent in the past hour as we clamber down the mountain to Naduri along a muddy, slippery clay hill shredded by roots and rain, our spirits and patience plummeting with the descent.

It's almost too much for one in our group, thirtysomething Alison, whose knees have seized up. She eventually reaches Naduri at sunset, arms draped over her porter, Robert, and trek leader, Jim Drapes.

With 25 local crew members and porters beside us - some of whom have walked the track hundreds of times - the best trekking gear and walking poles to aid us and a diet of two-minute noodles, Spam and energy bars to nourish us, our situation is almost shamefully lavish compared with that of the diggers who fought alongside Norris.

These inexperienced "chocolate soldiers" of the Australian Army, so named because they were expected to melt under the pressure, faced acute shortages of food and shelter and even tore out the backs of their shorts because dysentery was so dire.

As we leave our rest spot on the ridge and feel the hot sun again, we begin to realise why the ragged, bloody heroes of the Maroubra Force have passed into Australian folklore.

"It's one of our most significant battles ever," says Drapes, head of Back Track Adventures, one of about 40 companies that regularly lead tours on the Kokoda Track.

Between July and November 1942, about 1500 Allied, primarily Australian, forces fought the larger and more skilled Japanese forces along the Kokoda Track. Miraculously, despite being outnumbered more than five to one, they kept the Japanese from Port Moresby until they were so depleted they had to withdraw, the first major defeat for the formidable invasion force.

"The thing that really gets me, the thing that really affects me, is that these soldiers honestly and passionately believed that if they didn't stop the Japanese here then they'd be in their mother's loungeroom or their girlfriend's bedroom next. They honestly believed that," Drapes says.

The Australians' successful tactics of engaging and withdrawing, or slowly "leapfrogging" backwards to Port Moresby, were misinterpreted by military authorities at home. After the battle, the diggers were branded cowards. "It's not the man with the gun who gets shot but the rabbits that run," Commander-in-Chief Sir Thomas Blamey told those who were left of the 21st Infantry Brigade at the end of 1942. It would be another 60 years before Australian authorities recognised Kokoda as one of the nation's finest military campaign.

In the past decade or so, an almost inexplicable national resurgence in interest and pride in Anzac wartime achievements, including those in Papua New Guinea, has elevated the Kokoda Track from historical theatre of war to tourist destination and an important rite of passage for Australians. About 70 trekkers walked the track in 2000. This number had risen to more than 3000 by last year.

The Kokoda Track Authority was established in 2002 and, in anticipation of waves of visitors, campsites were created and the track was widened recklessly. Track permit fees were misappropriated and villagers, who reaped few of the benefits of tourism, became hostile towards trekkers. A loose coalition of Australian trekking companies urged the Australian government, which funds the authority in a bipartisan agreement, to sack the management committee and appoint Australian workers familiar with the track and the country to key positions. Each was responsible for a local trainee. In 2010, the last of the Australians finished up and the authority reverted to local management.

Money now filters into villages via transparent bank accounts and those on the ground report growing interest and a sense of pride in the track's tourism industry among villagers along the way.

The rising popularity of the track has resulted in mishaps. Six trekkers have died since 2006 and about 50 people each year are evacuated - giving it a fearsome reputation. But safety protocols have improved and track repairs are under way. Trees are being planted, the track is being narrowed, rangers have been installed and repair crews in each village are being trained in drainage techniques and evacuation procedures.

For the most part, I find the track narrow, winding and muddy - but negotiable. "It's the best I've seen it in 10 years," Drapes assures us.

I take his word for it, as we continue the relentless uphill-downhill-uphill routine. Each new hill is a new chapter; each time Drapes alerts us to a long and slippery descent, our shoulders sag. The descents have become the bane of our group's existence: tough on mostly middle-aged knees, making it hard to stay focused and impossible to stay upright.

My porter, Ronald, a gentle and almost painfully shy man from the village of Efogi, about halfway along the track, follows me and holds my bag straps like a horse's reins, ready to hoist me up if I slip, although I still manage some spectacular falls. Put simply, it's hot, dirty work for eight long days.

Still, at 24, I have youth on my side and the walking pace is reasonably slow. As advised, I started training three months ago, with daily one-hour walks building up to a couple of four- and five-hour bushwalks a week. All but a handful of our group have hired personal porters to carry their packs, leaving us with five-kilogram day packs. Once I get past Naduri on day three, I'm feeling physically good. I'm losing weight, my mind is clear and I have sufficient energy, mentally and physically, to tackle hills for days.

Emotionally, though, I'm spent.

Compared with the dry and dusty fringes of Port Moresby, the hilltop village of Kokoda, where our trek begins, feels like a mountain utopia. We're welcomed by dancers in traditional dress and crowds shouting "Ora! Ora!" (welcome), and we go to sleep to the sound of our porters singing Seventh-day Adventist hymns in beautiful eight-part harmony. Already, I sense this will be an emotional experience.

The next night we reach the Isurava battlefield, an eerie opening high in the hills where in August, 1942, the poorly equipped 39th Battalion, average age 18 and at that stage the only Australian unit confronting the Japanese, dug in for weeks until reinforcements from the 21st Brigade arrived. Drapes tells us vivid stories of the bravery of the soldiers at Isurava: the injured men who were operated on at "surgeon's rock", a large flat slab we pass the next morning; and the Bisset brothers, who sat at an inconspicuous spot just metres before the slab.

It was here, Drapes says, that the digger Stan Bisset held his brother, Butch, in his arms as he died from a machine-gun wound to the stomach. For six hours Stan and Butch, the best of friends, sat just off the track as the battle continued around them, laughing, crying and remembering the good times of their childhood, as the life slowly ebbed from Butch.

Despite having walked this route 29 times, Drapes falters a little when he tells us that the diggers would sing Danny Boy whenever they passed this spot, as a sign of respect for the much-loved Bisset brothers.

We pass almost untouched battle sites, spent ammunition, parts of Bren guns, empty tins of bully beef, live grenades and bullet holes in trees that vividly evoke the war. As we weave through the hills and among the reminders and stories of battle, I'm profoundly moved.

But on a trail of suffering and loss are moments of beauty: tropical flowers bursting with colour; pristine creek crossings; the cheeky pranks of our overladen porters; and an introduction to a surviving Fuzzy Wuzzy Angel, the name given to PNG natives who carried injured men to safety and ran supplies along the track for the Australians during the war.

At Naduri, Ovoru Nidiki recalls his wartime experiences. Through his son, Andy, who is our trek co-ordinator, the 106-year-old Nidiki says villagers were enlisted to work as carriers when war broke out. "We saw women killed and heads buried in the ground with the legs sticking up," he says. "It was very troublesome for us but we had to do the job."

Nidiki was shot at by the Japanese at Mount Bellamy but the bullets flew past him, one of many near-misses. Years later he was on a plane from Port Moresby to Naduri that overshot the runway and toppled over a cliff. "They offered me a helicopter to get home and I said, 'No, I've touched the ground, I won't fly again'," he tells us.

Like Nidiki, the Koiari people of the Owen Stanley Range, who live in primitive but manicured villages along the track and comprise our crew, are gracious and polite, with a streak of mischievousness.

Each night as we go to bed against a silhouette of the mountains and paw-paw trees, exhausted and aching, our crew sings hymns to pass the time. None of the dreadlocked teenage porters, nor Matthew, our burly trek leader from Efogi, with calves the size of tree trunks, are too cool to sing.

The lyrics seem particularly apt - No, no it's not an easy road / But Jesus walks beside me / And brightens the journey - for our porters, who are dwarfed by huge packs loaded with pots, pans and our personal belongings.

Even as we approach our final hours on the track, a hot and steep climb from the gushing Goldie River up to Owers' Corner, they are still singing. For Alison, their song is what gets her through. For me, it's the soundtrack to an expedition through wild jungle, war history and the world of the Papua New Guineans.

We celebrate the track's end and our achievement with handshakes and hugs over cold drinks and sandwiches.

Then silence, as we take in the number of dead listed on the memorial arches at Owers' Corner - about 625 Australians and 4500 Japanese.

"It will never be the same, silent, sweet-smelling jungle track where man and his indecencies were almost known," concluded Sir Kingsley Norris, whose words are inscribed on a memorial at Kokoda.

"It is a trail of blood and iron now and in the memory of this generation will remain so."

Rachel Olding travelled courtesy of Back Track Adventures and the Papua New Guinea Tourism Promotion Authority.

FAST FACTS

Trekking there

Back Track Adventures, founded in Brisbane in 1984 and with 10 years' experience in Papua New Guinea, runs 11-day Kokoda trips for groups of up to 20. Trek packages cost from $4580 a person from Sydney and $4170 a person from Brisbane. This includes Air Niugini flights to and from those cities, all food, two nights' accommodation in Port Moresby and one night in Kokoda (either end of the eight-day walk), tent accommodation on the track, guides and internal transfers. Air Niugini doesn't fly from Melbourne so trekkers need to arrange connecting flights to Sydney or Brisbane. A personal porter costs an extra $640; otherwise, you need to carry about 15 kilograms of gear in your backpack. Phone (07) 3850 7600, see trekkokoda.com.au.

Fitness

At the time of booking, Back Track provides a recommended three-month training plan. Most people should start training earlier unless they're already very fit. Hill training and long bushwalks are most beneficial and you should train with the weight you will carry (even if you are walking with just a day-pack) and the hiking boots you intend wearing. It is nearly impossible to prepare for the humidity, heat, rainfall and mud. Inexperienced walkers shouldn't be deterred, however — with proper training, the track is completely manageable. The best preparation, the Papua New Guinean locals say, is to remain relaxed.

A little knowledge of the Kokoda Track campaign during World War II will make the trek more interesting and rewarding.

Equipment

Back Track provides a detailed list of equipment required, including boots, light-weight quick-dry clothing, walking poles, water bottles, sleeping gear and medications. All tents are provided.