Tarek el-Kowmey, 45, points proudly to the banana trees he grows on what was once Sahara sands near the Desert Development Centre, north of Cairo, where scientists experiment with high-tech techniques to make Egypt's desert bloom.

"All of this used to be just sand," he said. "Now we can grow anything."

With only five percent of the country habitable, almost all of Egypt's 74 million people live along the Nile River and the Mediterranean Sea. Already crowded living conditions -- Cairo is one of the most densely populated cities on earth -- will likely get worse as Egypt's population is expected to double by 2050.

So the government is keen to encourage people to move to the desert by pressing ahead with an estimated US$70 billion plan to reclaim 3.4 million acres of desert over the next 10 years. Among the incentives are cheap desert land to college graduates.

But to make these areas habitable and capable of cultivation, the government will need to tap into scarce water resources of the Nile River as rainfall is almost non-existent in Egypt.

The plan has raised controversy among some conservationists who say turning the desert green is neither practical nor sustainable and might ultimately backfire.

Anders Jagerskog, director of the Stockholm International Water Institute in Sweden, questions the wisdom of using precious water resources to grow in desert areas unsuited to cultivation and where water will evaporate quickly under the scorching sun.

"A desert is not the best place to grow food," he said. "From a political perspective, it makes sense in terms of giving more people jobs even though it is not very rational from a water perspective," he added.

REGIONAL TENSION?

The scope of the reclamations could also add to regional tension over Nile water sharing arrangements as in order to green its desert Egypt might need to take more than its share of Nile water determined by international treaties.

Egypt's project to reclaim deserts in the south, called "Toshka", would expand Egypt's farmland by about 40 percent by 2017, using about five billion cubic metres of water a year.

That worries neighbours to the south who are already unhappy about Nile water sharing arrangements. Under a 1959 treaty between Egypt and Sudan, Egypt won rights to 55.5 billion cubic metres per year, more than half of the Nile's total flow.

Ethiopia, where the Blue Nile begins, receives no formal allocation of Nile water, but it is heavily dependent on the water for its own agricultural development in this often famine ravaged country.

"The Toshka project will complicate the challenge of achieving a more equitable allocation of the Nile River with Ethiopia and the other Nile basin countries ," said Sandra Postel, director of the US-based Global Water Policy Project.

"Egypt may be setting the stage for a scenario that's ultimately detrimental to itself."

But other experts suggest that in the delicate arena of water politics, it may be more of an imperative for Egypt's government to mollify its own population rather than heed its neighbours concerns.

Overcrowding is straining infrastructure in the cities and the government is worried that opposition groups such as the Islamist Muslim Brotherhood, which has a fifth of the seats in Parliament, might capitalise on discontent.

"The government feels it needs to reduce the number of people in high density areas, which puts a lot of pressure on resources like fertile land," said Mostafa Saleh, professor of ecology at Al Azhar University in Cairo.

"They are trying to spread the population to other parts of the country."

DESERT TOURISM