After being examined at the islands' TB clinics, about one-quarter of the sick have been found to be infected with multi-drug-resistant TB (MDR-TB), a dreaded modern manifestation of a disease that still ranks among humanity's greatest killers.

From the Torres Strait islands of Saibai and Boigu, the sickest are then flown to hospitals in Cairns, Queensland, where access to powerful second-line drugs and intensive treatments mean the difference between life and death, or life and profound disability.

This fragile lifeline between PNG and ''the Other Side''- to borrow the PNG vernacular for the land beyond the invisible border - is no answer to the health crisis that extends across the impoverished South Fly region, or the disease emergencies, such as cholera, tuberculosis and malaria, that fester within the settlements crowding the muddy shores of the provincial capital on Daru Island.

As a health strategy, fleeing to Australia is not equitable - it's grossly inadequate, and it's random. But for all that it is - or was - something for those with the wherewithal or inclination to make the journey.

In theory, it has also only been an avenue open to those people from the cluster of border communities allowed free movement under the Torres Strait Treaty. But such protocols have not always been observed by doctors and nurses in the Australian clinics.

''I'm not an immigration official,'' says Dr Graham Simpson, a respiratory specialist from Cairns who has regularly worked at the clinics. ''We treat sick people.''

A recent decision by Queensland Health to stop funding the Torres Strait clinics has cracked open a political, diplomatic and ethical fault line on this most sensitive frontier, shining a spotlight into PNG's neglected tuberculosis epidemic and the broader health catastrophe it is symptomatic of.

Australian self-interest has made the issue more intense. If evolving, drug-resistant variations of tuberculosis are allowed to brew just offshore, what would stop them crossing the border?

Amid an outcry that Queensland Health's decision would condemn people to death, Canberra entered the fray, declaring it would invest urgently and heavily in Western Province to help PNG better serve its own citizens. As a strategy this appears beyond debate - why rescue just the few when there is an opportunity to help many?

Because, say the critics on both sides of the border campaigning against the closure of the clinics, PNG's beleaguered health system is a long way from being capable of caring for these patients, and lives will be sacrificed in the attempt.

In highlighting the scale of the failures within the PNG health system - widely acknowledged even by the PNG government as a wreck - the story of the Torres Strait clinics raises the fraught debate about the effectiveness of aid, and about how to turn Australia's $400-million-a-year aid to PNG into real benefits for its people.

Coming on the heels of two independent evaluations of the performance of Australian aid - one last year focused on PNG, and one in May looking at AusAID's role internationally - new strategies are being rolled out on the ground in PNG. The TB crisis, and the closure of the clinics, lends sudden urgency to these efforts.

Daru General Hospital, and the vast, impoverished Western Province region it serves, provides the theatre for a bold real-life experiment in which the stakes could not be higher.

Daru is the notional capital of Western Province, but the powerbrokers have long since moved north up the Fly River, closer to the action of Ok Tedi Mining's copper operations. They left behind a dysfunctional, marooned island city with a pot-holed airstrip, a tenuous water supply, an estimated 15,000 people - many crowded into shanty slums - and a hospital reputed to be one of the worst in the nation's failing government health system.

In ''poor old South Fly'', observes AusAID's PNG health program director, Dr Geoff Clark, ''seriously, God forgot them''.

Daru General Hospital struggles to find clean water, let alone medical staff. Buildings and equipment are dilapidated and broken. When The Age visited, neither the X-ray machine nor the tiny pathology unit was working.

Each morning, the sick are turned too quickly out of 90 beds to accommodate the next wave. Many come from ''the corners'' - settlements that are home to the diaspora of Fly delta people who flock to Daru because they can't get access to basic health services, schools, banking and communications in their home villages, or because they have lost their gardens to rising king tides or to shifts imposed on the Fly River from the sediment washing down from Ok Tedi. With underlying malnutrition and overcrowding, disease spreads rapidly through the corners.

Men, women and children share crowded wards. There hasn't been a delivery of basic medical supplies in months - though this is a complaint common in health facilities right across the country. The hospital's caretaker chief, Dr William Waro, says he has run out of anaesthetics and antibiotics. Meanwhile, he is struggling to find money to keep mopping up the aftermath of a cholera epidemic last year which officially claimed between 200 and 300 lives, but which local health workers say may have killed many more.

Dr Waro is worried that when village people from far-flung parts of the province converge on Daru next month to collect their annual payments from Ok Tedi, cholera will again capitalise on a crowded city weakened by underlying poverty and sickness and lacking a functional sanitation system.

Meanwhile, the major daily preoccupation of the hospital is tuberculosis, a serious but treatable disease spread by inhalation of airborne droplets and which thrives in the ghettos around Daru. TB in PNG has increased by 42 per cent in the past decade and is still rising, according to national health data. The World Health Organisation says about 3600 people in PNG die from TB every year, though uncertainties around surveillance and diagnosis mean the toll may well be higher.

There is also mounting concern about the level of MDR-TB brewing within the population, and the possibility of the nightmare scenario of extreme drug-resistant strains (XDR-TB).

While there is little data available on TB drug resistance patterns in PNG due to the lack of pathology facilities, about one-quarter of the patients from Western Province turning up at the Torres Strait clinics have been found to have MDR-TB.

Dr Simpson was lead author of a recent journal paper which indicated that MDR-TB was highly prevalent in PNG, and the risk of more extremely resistant strains emerging was high.

Sister Lesa Konga, the TB ward's charge nurse at Daru Hospital, tells The Age that she has lost four patients in the past few days, two of them from drug-resistant strains. ''People come [for treatment] too late,'' Konga says. ''By then the bacteria has already invaded their body systems.'' This will be overcome by increased surveillance, screening and supervision of medication out in the communities, she says.

THE hospital beds are full. The patients include two little girls with TB meningitis, the infection having damaged their brains. One, Felina, is seven months old. Next to her lies six-year-old Christina, her eyes vacant and staring. Emaciated, she weighs just eight kilograms. Her mother, Mae, says that only a few months ago she was a healthy, active girl. Even if these girls recover, it is likely they will be profoundly disabled. Had they been treated early, or had access to the intensive drugs and physical therapies available in Cairns, they may well have survived able-bodied, says paediatrician Dr Naomi Pomat.

Konga says that outreach programs sending visitors into communities to check that people are taking their medications are delivering heartening results, cutting the number of cases of relapses and treatment defaulters. ''I am only receiving new cases. But these are rising.''

She is concerned that when the Torres Strait clinics close, ''the influx from those patients will be piling up here. We need to get some more beds and buildings to receive them, stabilise them, and funding for more staff.''

Under an agreement brokered last week between the PNG and Queensland governments, the 50 current patients from the Torres Strait clinics - most of them with drug-resistant disease - will begin transferring back to PNG for treatment in the next few months.

Meanwhile, new facilities and programs are being fast-tracked at Daru Hospital. AusAID is building a TB isolation ward as well as investing in new communications and records facilities, improved pathology services and programs to train and fund more skilled staff. A TB co-ordinator has been appointed and a specialist doctor will begin work from the hospital soon. Plans are being drawn up to equip a health boat to begin regular visits to outlying communities.

Last year's investigation of AusAID programs in PNG over the past decade was deeply critical of Australian aid to PNG, and urged a major recasting of the philosophies underpinning it. ''There is widespread dissatisfaction with the aid program in both PNG and in Australia,'' it concluded. Programs lacked impact and value for money; meanwhile, ''service provision in many parts of the country is collapsing''.

A core finding was that projects were spread too thinly. It urged less breadth and more depth. This has been a key consideration in evolving AusAID's new health strategy, supported by $82 million this year, says Dr Clark. It has particular focus on family planning, child immunisation and maternal health - maternal death rates in PNG are among the highest in the world. A central commitment of the strategy is an agreement by Australia to fund and distribute essential medicines to all functioning aid posts, health centres and hospitals across the country in 2012, and then move to fully outsource the whole system under PNG management, co-funded by Australia.

Projects to revitalise medical training are another priority. PNG has one of the worst ratios of medical expertise in the world - only 5.8 doctors, nurses and midwives per 10,000 people. Last month eight Australian and New Zealand midwifery specialists arrived in PNG to begin a program to train 500 midwives by 2015. At present there are only 152 practising midwives, and an annual birth rate of 200,000 deliveries, the vast majority of which are unsupervised.

Western Province, which despite its resource richness has some of the nation's worst health indicators, is one of five provinces that will now be the focus of intensified, targeted Australian support in pilot programs focused on delivering assistance directly to the provinces, which had been hamstrung by a lack of funds flowing from Port Moresby to meet the needs of rural and remote communities.

In the wake of the Queensland decision to shut the Torres Strait clinics, ''the spearhead has been the TB program, which we've had to get up and running in a very short period,'' says Dr Clark. ''You can't expect people not to cross the border and get health services if you don't provide them with an alternative. If it was my child, I'd cross the border too.''

But bringing about meaningful change ''is a huge challenge'', says Alice Honjepari, director of rural health in Western Province. She believes PNG should take responsibility for the TB programs, and welcomes the promises being made by AusAID for more assistance to her vast area of responsibility. But she is cautious about the prospects.

Improving health services will require more than investment in training, staff and equipment, she says. Unless those facilities are supported by communications, transport, education and secure food and water, the underlying problem of recruiting and retaining skilled staff to remote postings will continue to undo the best intentions.

Dr Stephen Howes, a development specialist from the Australian National University and one of the authors of last year's review of Australian aid to PNG, says it is much too early to say whether the new PNG health strategy will work, ''especially given the disappointing historical results, the dysfunctional nature of the health sector in PNG, and the limited leverage of our aid given the resource boom.

''Therefore, any justification of denial of health services to PNG citizens in Australia on the grounds of the difference our aid to PNG health can make is premature, at least for now.''

In Cairns, Dr Simpson says he and his colleagues also want to see PNG given support to deal with the TB crisis on Australia's doorstep. But he's concerned that haste and political expediency will cost lives, and wants the World Health Organisation to intervene. ''We need a referee in here to say when it is safe and OK to withdraw services.''