Supporters of the Bushmen, including several international pressure groups, say Botswana's government wants unimpeded access to any mineral and diamond reserves which might be beneath the Kalahari.

But the government says the Bushmen must be better integrated into mainstream society if they are to benefit from education, medical services and job opportunities.

Diamond reserves have helped transform Botswana into one of Africa's most sophisticated economies, with one of the continent's highest per capita incomes and model health and education services.

Authorities set up a special court in the Kalahari to allow more Bushmen to testify. The desert hearings are expected to last until July 30 when the case will move to the High Court's regular seat in Lobatse.

Southern Africa's Bushmen have lived in the region for thousands of years and many still survive as traditional hunters and gatherers in an unforgiving desert environment.

A victory for the Bushmen would give them the right to stay in the Kalahari - an important symbolic advance for Africa's dwindling populations of traditional hunter-gatherers.

About 2,500 Bushmen have been relocated over the past 18 months from the Central Kalahari Game Reserve, located in the middle of huge and sparsely populated Botswana.

Botswana's treatment of the Bushmen has become an international issue with celebrities weighing in and major diamond producer De Beers, which has massive operations in Botswana, coming under pressure.

President Festus Mogae recently suggested his government would pursue the case until the Bushmen are legally barred from the Kalahari.

"This is a very disturbing remark indeed for the head of state of a supposedly democratic government to make about the due process of law inside his own country," said Stephen Corry of Survival International, a British-based organization which has championed the Bushmen's cause.