Vaudine England – His long flowing hair and tight jeans mark him out as a young intellectual even before he starts talking.

"What are you doing here? Do you have a reason to be here?" asks Didiek Eko Yuana. He is part of a 41-strong team of volunteers from the mainstream Muslim organization Muhammadiyah. A student of international relations in Jogjakarta, the university town in central Java, he is into his second week of traveling in Aceh by bus bringing medical aid, food and friendship to earthquake and tsunami victims.

Didiek, 23, has seen all sorts of things on his first visit to Aceh, which is a very long way from Java. He has helped carry corpses, hundreds of them, bloated and distorted beyond recognition, and stinking horribly.

He has found his Acehnese compatriots, those who survived the earthquake and waves of December 26, huddled in steaming rain under scanty sheeting, scrabbling for food, shaking with trauma.

And he's now seeing a second tsunami – the waves of foreigners pouring into one of the most sensitive, closed parts of Indonesia.

He approaches me because he's getting worried about all these foreigners. Apparently reassured that I am not an aid worker, nor seeking religious converts, he starts to share his concerns.

"I think it's OK to have these foreign groups. But I hear of problems because lots of organizations are coming and they all have their own interests. And there are so many of them," Didiek says. "It's OK that lots of people want to help the Indonesian people, but this area is still in conflict so it can be dangerous. There are so many competing interests here."

He's expressing a widespread and understandable feeling. In the past few days, the number of foreign aid groups in Aceh, a province with a pre-tsunami population of about four million, has rocketed into the hundreds.

Landing at the airport, on a United States military C130 Hercules cargo plane bringing, say the signs on its cargo, "USAID from the American people," it's clear that a system and control over the aid is virtually non-existent. It feels like landing in the middle of a movie set.

Choppers are constantly whirring overhead, US soldiers are charging around in forklifts, Australian and British chaps in uniform are shaking hands, French "WATSANS" – water and sanitation experts – are offloading their tubes. Mexicans, Yemenis, Malaysians, Japanese, Spanish, you name it, their representatives are here in the mud and noise.

Disaster chic is much in evidence. The gum-chewing blonde from Project Hope has found her camouflage khaki pants and beige T-shirt for her flight to Aceh, presumably to blend in better. The reporters from Anchorage, Alaska, here with the US troops flying this C-130, are almost indistinguishable from the soldiers they're covering.

Aid workers have matching outfits, logos to the fore and banners high, as if they were branding their good works. TV crews swish through trailing wires; reporters perched on the bonnets of cars stuck in the mud swear at satellite phones; crates of mystery equipment clutter the tarmac.

Back from the hubbub, around a small mosque with a pleasant sitting-out area, are the Indonesians. Some of the men are preparing to wash before midday prayers. Many are watching all the excitement with bemusement and a growing sense of dislocation. Occasionally, in among the foreign men, and women, a dapper Indonesian air force officer in neat blues can be found.

It's enough to make any nationalist heart beat stronger. And there are many nationalist hearts prone to feeling under threat in Indonesia: a lot of pride and dignity is at stake in the midst of this crisis. "If it feels odd to us, imagine how it feels to an Indonesian," notes a European aid worker.

Typical scenes are unfolding: fleets of white Landcruisers squeezing the poor man's bicycle or rickshaw into the mud; Indonesian soldiers trying to guard a United Nations office being ignored as crowds of aid workers and journalists pile past them into a meeting, the local drivers or translators shouted at by stressed-out foreigners on a deadline.

At this level, it's easy to see how a crisis could blow up anytime soon, when tempers flare between the rich, well-fed do-gooders of the West and the offended, under-funded representatives of the East.

That's why the smarter aid groups, such as Save the Children, which has worked in Aceh continuously for 30 years, or the International Committee of the Red Cross, have no problem with the so-called "new restrictions" handed out by the Indonesian authorities this week. The restrictions require aid groups and other foreigners to get permission from the military before leaving Aceh's major cities.

The government would like to know who is on their territory and what they are doing. Old pros in the aid business agree that the worst problems arise when cowboy outfits of inexperienced donors barge into a place they know nothing about and start disrupting delicate power balances on the ground.

A colonel from Indonesian military intelligence briefed aid groups on Monday and, said participants at the meeting, indicated that the free-for-all in the immediate crisis of the tsunami needed to be brought under control.

So the government requires lists of every foreigner in Aceh, with their passport details. It also wants to be informed of where foreigners are working, when they are taking trips outside the capital and to where.

"The regulations are aimed more at the new groups who the Indonesians – and frankly some of us – have never heard of. It's right the government finds out who they are," says an experienced international aid director, who asks not to be named.

At this level anyway, Indonesian wariness about these new visitors pouring into Aceh is only logical and wise. "The tolerance levels out here are usually pretty good, but considering the trauma, things could snap pretty fast. One of our staff has lost 21 relatives, his entire extended family. For sure there will be overreactions to some of the irresponsibility which is arising," says the aid director.

Cecile Sorra, a communications associate for Catholic Relief Services, concurs: "The government recommends it's best not to drive outside Banda Aceh at night, and we agree."

Her colleague Wayne Ulrich, CRS Emergency Coordinator, reckons it's likely that "there'll be incidents – after all, three weeks ago here there was martial law. Whatever we do in this province, we have to be aware a conflict was under way."

He and other aid experts agree the priority must be to place most decision-making power in the hands of Indonesian staff, and to work in partnership with Indonesian organizations.

"We're notifying the Indonesian authorities of all our field operations, it's a matter of keeping them informed," says Martin Unternaehrer, communications coordinator for the International Committee of the Red Cross. "In a conflict situation we need to know where our teams are going, so these [requirements] don't hinder us. We are working with a system with which we can work."

But this is Indonesia, and a low-intensity conflict between the armed forces and separatist rebels here in Aceh has simmered for decades. As a result, there is another level of negotiation under way – about who is in charge.

Contrary to most daily news reports, the real jockeying for power is not between foreigners and Indonesians. Foreigners are often mere tools in a competition for power and wealth which is always being played out within Indonesian society. Understanding this domestic power struggle will be key to survival of any foreign organization now working in Aceh, old hands agree.

Nor is this struggle necessarily a war between the armed forces and the separatists, although that will be the excuse used to control foreigners and behind which competition for local wealth-generating opportunities will continue.

Several aid workers with previous experience in Aceh joke that if we believe the figures given by official sources of how many rebels have been killed by soldiers in recent years, then the rebel forces would all have been killed off many times over.

There is simply no independent way to judge the long-running conflict between Jakarta and Aceh. Each side offers propaganda, claiming victories here, and abuses by the other side there. Two years ago, foreign-mediated attempts at a cease-fire and a negotiated settlement (under the auspices of the Henri Dunant Center, now renamed the Humanitarian Dialogue Center) were brought to a halt.

Since then, the only certainty is that a struggle over rich resources – from oil and gas on the north coast to marijuana plantations in the hills – has continued, with the Acehnese population ignored and abused in the middle. Battling over the aid largesse now at the disposal of Indonesian leaders – civilian and military – is intense and all-important.

And the likely brutality of these negotiations for power will catch some of the foreign aid groups off guard. "There was a large earthquake and then a tsunami here. But the Indonesian government is still the Indonesian government. The armed forces are still the armed forces," an aid worker says.

Veterans of the Indonesian millieu speak loosely of an East Timor scenario. This means that foreigners will be the football played by Indonesian competitors for influence. Security problems will occur – and will be created – in order to thin out out the field and gain advantage, and to discredit opponents within the domestic political arena.

In East Timor in 1999, local militias set up and funded by the Indonesian armed forces were used to create conflict, repress the local population and terrorize foreign reporters and aid workers. In Aceh in 2005, local thugs and imported "Islamists" sponsored by shadowy military figures (many of them the same individuals that were involved in Timor) are already present.

It's not hard to see what could emerge: a thwarted local population, a military still able to operate with impunity, an over-bearing foreign presence and a greedy political elite from Jakarta.

The violence in East Timor left thousands dead after the territory voted for independence in a UN-sponsored referendum. The aftermath was brutal.

Despite key differences between the two territories, experienced aid workers fear similar violence in Aceh. "I think it's inevitable actually," says the director of one large aid organization. "Lots of people don't understand the complexities here, of security, religion, culture and trauma – it all adds up to a volatile mix."

Another international aid worker with a long track record in the country agrees: "Yes, this is the danger. The statements by the army about controlling foreigners here are intended to push civilian leaders back in Jakarta. And the civilian politicians will seek to use the foreigners to extend their own influence against the military. It's a negotiation process, and eventually a compromise will be reached. "But nasty things can happen in the course of those negotiations."

He and other seasoned observers are just waiting for the first "security incident" – when an aid worker is shot or kidnapped, when a mysterious shoot-out happens close to a foreign office or home.

Controlling security is the army's prerogative and a destabilized environment gives it more room to wield power. That is what happened when the Timorese militias, allied with the military, attacked foreigners in 1999 – the same military came in pledging to restore order and protect the foreigners.

But "security incidents" might also be created by civilian authorities, to make the army look bad, and to bring more of the goodies now available in Aceh under civilian control.

Deep schisms persist in Indonesian society, between the population center of Java and Aceh, between the military and the civilians, between new president Susilo Bambang Yudhoyono and his hyperactive vice-president Yusuf Kalla. Negotiations across these divides will determine the future shape of Aceh's aid effort.

Looking further ahead, it will determine to what extent the Acehnese will want to feel part of the Indonesian nation.

Already the invective is flying. Radical Islamist groups – such as Laskar Jihad, which terrorized Christians in the Maluku islands in recent years, or the Majelis Mujahidin, which wants Indonesia to be an Islamic state - are complaining that Acehnese seem to see foreigners as more friendly than their own compatriots.

Some of these radicals are being flown up to Aceh, this time in Indonesian military planes, and are feared as shock troops used by some generals when they want to destabilize a situation.

On previous trips to Aceh, these extremists were told to go away in no uncertain terms. The Acehnese have never needed to be told how to follow their own religion.

It is this pride which helps feed the separatist impulse. A sympathizer of the Free Aceh Movement (GAM), at a village near Banda Aceh, says that the community around him is all in favor of GAM but too scared to talk about it. The last thing anyone wants is Javanese soldiers patrolling their homes, he says.

"Everybody here is very careful. People are traumatized and we don't want soldiers here," he says. He fully expects more exchanges of gunfire but assumes they will come from the armed forces. He says the GAM fighters he knows are staying in the hills.

"They will not create incidents because they know this is a national disaster and people are suffering. They also want to protect foreigners."

Analysts have long pointed out that GAM badly needs international support and is unlikely to be the source of attacks on foreigners.

"But there is always the false GAM, the soldiers dressed up as rebels, and they will create incidents until Aceh is destroyed," claims the GAM sympathizer, illustrating the circles within circles that often dominate politics here.

A pro-military friend in Jakarta complains about foreigners setting up "colonies" all over Aceh, blaming the president for letting them in so easily. He says the army is likely to either plan or bumble its way into a security crisis, which will have the effect of scaring foreigners out of Aceh.

Several UN and other aid workers expressed worry too about foreign activists who support the insurgency and are rumored to be using the current opening to visit friends in the separatist movement. "Frankly, that's the last thing we need, people likely to polarize the situation around ideology when we're still trying to reach and feed survivors," says a concerned aid worker.

Almost forgotten, as usual, in the midst of this jockeying for clout and cash, are the Acehnese themselves.

While competition for lucrative road rebuilding contracts ensues in Jakarta, no government work whatsoever is seen on a drive west of Banda Aceh, past the town of Lhok Nga. The road stops at a collapsed bridge, making land access to the impoverished south coast impossible. Mountains of debris are stacked along the same road where mountains of corpses were piled last week.

The dead are still being discovered, mass graves are still filled. Flooded wastelands stretch from sea to mountains with often only a mosque left standing.

A piece of sacking has become a sign pleading for information about loved ones. It is tied to a tree on a beach which once hosted late-night nipa huts good for a drink and a bit of fun.

Three soldiers draped in M16s are chatting with a man collecting scrap iron. A Malaysian team is dispensing medicine under a tent. The Justice Party from Jakarta, a growing Islamist organization, has jeeps here advertizing their widely appreciated emergency work.

But no one's fixing the bridge or the roads, not yet. Locals have thrown together a raft from battered oil drums and stray planks. Homeowners are moving one heap of rubbish at a time. Amid the blackened skeleton of a community, one porch boasts a pink table cloth on a rickety table, a lone statement of hope.