Everyone wants a piece of Cambodia's ancient temples, but greed could sound their death knell, reports Rosita Boland in the second of a two-part series.

The Irish-themed pub abroad has become a yardstick in the economy of global tourism: if your town has one, it means you are firmly inked in on the international tourist map. Molly Malone's opened last autumn in the tiny Cambodian town of Siem Reap, and is marketed as the town's "first authentic Irish pub".

Siem Reap is 6km from the World Heritage Site of the Temples of Angkor, an extraordinary and beautiful complex of temples. They date from the ninth to 15th centuries and were built by the Khmer kings as an administrative and religious centre. What remain today are hundreds of temples and palaces, only some of which have been de-mined and reclaimed from the jungle, and are open to tourists. Most of those are in the main Angkor complex, although the outlying temples extend across 400km.

Two years ago, when travelling in southeast Asia, I filed a report from Siem Reap which stated: "Right now in Siem Reap, two things are very clear. The town is on the cusp of becoming a major international tourist destination and a specific group of people are becoming obscenely rich." At that point, Cambodia was receiving 270,000 visitors a year, 90,000 up on 2002. Last year, the figure was 1.05 million, and the vast majority of those tourists visited only Angkor, with the largest percentage being South Koreans, Japanese and Americans on package tours. The Temples of Angkor are now on the hit-list of every backpacker in southeast Asia; a "must-see" destination now that vastly improved road and air access allows it.

Even in two years, the changes are staggering, and instantly visible before you ever leave the airport: the terminal building is brand new, and several times bigger than the one I flew into in 2003. But the hotels show the most telling change of all. It's 7km from the airport into Siem Reap, a journey which I made largely in darkness two years ago. This time, virtually the entire route is lit up by scores of vast, multi-storey hotels, some still under construction, men working by the light from generators.

The war is over now in Cambodia, but it will take another generation for the deep scars left by Pol Pot's regime to heal. More than one million displaced people were executed or died during that time. Communist Khmer Rouge forces captured Phnom Penh in 1975 and ordered the evacuation of all cities and towns. In 1978, a Vietnamese invasion drove the Khmer Rouge into the countryside. Thirteen years of fighting followed. It will take decades to make safe the country's six million unexploded mines.

Cambodia is still recovering from its horrible war, and remains a very poor country, where the average monthly wage is €18. But it has one priceless commodity - the Temples of Angkor. In less than three years, and with the open-skies policy into Siem Reap airport, the temples have become, for the first time in their long history, a truly international tourist destination.

Everyone involved wants a piece of them: the government, the private corporation that gets a large portion of the entrance fees for the temples, the conservationists, the international developers funding the new hotels, the local people and the tourists.

Angkor is now in real danger of being both sanitised and Disneyfied for tourists. Until a year ago, as is usual in tourist spots across Asia, local children sold postcards, trinkets and cold drinks outside every temple. They have now been banned from doing so by the government, as they were deemed to be annoying the tourists. Where are they now? Nobody in Siem Reap could tell me. However, one thing is sure: very few of them are at school.

Plan, the international child-centred development organisation working in 45 of the world's poorest countries, has an office in Siem Reap. It says there are 363 primary schools in the province of Siem Reap (which encompasses several towns), but only 13 secondary schools.

So the children have dropped out of sight. The monks, however, who come to Bayon and Angkor every day to meditate and pray, and who were threatened with expulsion in June 2002, were allowed to stay. In their colourful orange habits, they are apparently tourist-friendly, since they look so photogenic among the ruins.

Less lucky are the working locals who are not monks. In the last year, Cambodians have been denied access, after 6pm, to the much-used public road that runs through the temple complex. (Cambodians do not need passes to access the temple sites.) They now have to use a much more circuitous route.

Local people in Siem Reap are worried that even daytime access to the road will soon be denied to Cambodians. If this does happen, despite the size of the temple complex, it's entirely possible that a tourist could arrive on a package tour, stay in a hotel owned by someone from their country, such as Korea, have a Korean-speaking guide take them round the temples, eat Korean food in the hotel, and be completely cut off from any interaction with Cambodian people. How ethical is this type of tourism?

Being hundreds of years old, the Temples of Angkor are - obviously - not built to modern standards of access. You need to haul yourself up and down very steep steps, clamber over lots of uneven broken stones, and walk long distances, all of this under a very hot sun. The authenticity is part of what makes this place so special. You don't go to Blarney Castle, for example, and expect a lift to take you to the top.

Except it's a truism that the type of tourists a place receives dictates future development. The majority of Angkor's visitors are on package tours, and from what I see, they wouldn't be the youngest people in the world. A Hong Kong consortium has already pitched the idea of an escalator to take people to the popular, but steep, sunset-viewing point on Phnom Bakheng, opposite Angkor Wat. Thankfully, it's not there yet, but even the fact it has been talked about is significant.

Evidence of new and clumsy development is visible throughout the temple complex. A huge yellow sightseeing balloon, which looks both absurd and intrusive on the ancient skyline, is permanently tethered close to Angkor Wat. One afternoon, I watch tables being set up outside the Terrace of Elephants for the now-regular $70 (€52.59) son et lumiers shows over Bayon, followed by a buffet and fireworks, and billed as the "Mysterious Festival Angkor Night".

The sheer number of new hotels is causing its own serious environmental problems. Water is scarce and a lot of it is suddenly needed for all those thousands of new showers and toilets. Hotels are now pumping water from underground.

Last year, at a symposium in Siem Reap organised by the Japanese Conservation Team for Safeguarding Angkor, experts warned that the famous Bayon temple was in danger of collapsing, despite having endured 800 years. It sits on sand that is suddenly sinking, due to the amount of water being drawn off from underneath it. They asked that data be urgently gathered on the amount of underground water being collected by hotels.

It couldn't be more ironic: mass unplanned tourism endangering the very attractions that bring people here.

What's worse is that very little of the money being generated by these developments is going back either to the Cambodian people or to help conserve the temples. Most of the new bars in Siem Reap are leased by foreigners, and most of the new hotels have been built by foreign developers. A Japanese company and a Thai airline are behind the Mysterious Festival Angkor Night.

The sightseeing balloon is owned by Sokimex, the same company that receives most of the entrance money to the temples. The rest goes to the Apsara Authority, a state-run organisation set up for the protection and maintenance of the temples. Sokimex is a Cambodian petroleum company, which also supplies the government with military supplies. Deals are cut everywhere in Cambodia.

Angkor was designated a World Heritage Site in 1992: Cambodia had no money for its upkeep. Since then, more than €35 million has been spent by other countries on preserving and restoring the temples. Most of the money has come from UNESCO, Japan and France. As the temples are the property of Cambodia, members of the international community cannot stop developments they think are inappropriate; they can only advise, argue and plead. It's a situation where everyone feels compromised.

And then there are the plans for the new museum. There is a vast site in Siem Reap which currently has corrugated iron fencing around it and a sign declaring that this is where the new National Museum of Siem Reap will be. If you look through a gap, you can see hundreds of concrete girders bristling out of the ground.

The Angkor Conservation Office in Siem Reap is not officially open to tourists, but the offer of a donation will gain you entry. This is where hundreds of priceless statues from the temples are held to protect them from looters.

I ask if they will someday be returned to the temples. "No," says the man showing me around, "they will go to the new Siem Reap museum when it is finished".

A French man, Philippe Peycam, is the director of the Centre for Khmer Studies in Siem Reap. He has lived there for five years. Isn't it good, I ask him, that these artefacts will now be displayed properly in a museum and seen again by the public?

"It will not be a museum in the way we understand a museum," he replies, and explains why. The site is owned by the ministry of culture. It has, in the Cambodian way, done a deal involving an unspecified amount of money with a Thai company, who will fund the building of the "museum" in exchange.

"What they are are building is a hotel and shopping mall. The artefacts from Angkor will be there - displayed as part of the interior design. Like Las Vegas. I think it is disgusting. It is all about making money."

Mao Loa is the director of the Apsara Authority, which is responsible for the conservation, management and protection of Angkor. "We want tourists to stay longer in the area," she explains. Lao takes out drawings for the future planned developments around Angkor. There is a golf course on the drawings, right next to the entrance to the temple complex.

When asked about the new museum, Lao will not give a straight answer. Is the authority not responsible for the artefacts held at the Angkor Conservation Office? She agrees this is true. But she will not answer the question of what form the new Siem Reap National Museum will take, simply saying: "It will be a new museum for a new future".

Old temples, new future. When leaving Siem Reap, we ask the taxi to take the public road through the temples to the airport. I look at Bayon and Angkor one last time under sunrise. I will never return. I would be afraid of what I would see.

Rosita Boland and Frank Miller's trip to Cambodia was funded by the Development Education Unit of Development Co-operation Ireland

Rosita Boland's article and an extended gallery of Frank Miller's photographs are available on The Irish Times website ireland.com: www.ireland.com/focus/cambodia