British-based Survival International last month accused the government of shutting down the reserve as part of a stepped-up campaign "to remove the Bushmen and end their way of life".
"Armed police and wildlife scouts are camped in the Bushmen's reserve and are threatening to shoot them dead," it said.
But the government of President Festus Mogae flatly denied that the closure amounted to a clampdown on the Bushmen who had been waging a court battle since July last year over land rights to the Central Kalahari Game Reserve, one of the world's largest sanctuaries.
"That is false. There is nobody who has been ordered or forced to leave the game reserve. There is no policy of the government to force anybody out of the game reserve," government spokesman Clifford Maribe said.
Botswana parks authorities last week said in a statement that several police officers were assaulted in the game reserve when "the officers wanted to enter the compound of one of the witnesses in the CKGR court case to investigate a poaching incident".
The flareup in tension centres around a decision to shut down as of 1 September parts of the reserve due to an outbreak of sarcoptic mange found in the Bushmen's goats.
Survival International has dismissed the disease outbreak as a pretext to evict the few remaining Bushmen living in the reserve.
Bushmen have been moved to
New Xade, a resettlement town
The British organisation cites a statement issued by a group of veterinary scientists that ''this disease, while potentially serious in some populations, can be very easily treated in domestic animals with modern drugs.''
''Adequate control of infectious diseases in livestock is critically important, but measures should be proportionate and removing the animals from the park cannot be justified on grounds of disease control in this case,'' added the statement, signed by among others Professor Lord Soulsby of Swaffham Prior, House of Lords, Westminster and Ivan Horak, Emeritus Professor of Veterinary Tropical Diseases at Onderstepoort University, South Africa.
The statement was published in a Bostwana newspaper.
The organisation also says that up to 250 Bushmen still live in the game reserve in defiance of the campaign to resettle them, but the government maintains that only a few dozen are left.
The British colonial government created the Central Kalahari Game Reserve in 1961 in Botswana, then called Bechuanaland, to protect the San's hunter-gatherer lifestyle.
But the Botswana government contends that the San's traditional way of life is lost, and began relocating the Bushmen in villages outside the reserve in the 1990s.
San, who once numbered millions,
roamed southern Africa freely
The San are asking the High Court to declare that the eviction in 2002 of Bushmen to a new settlement called New Xade outside the game reserve was illegal.
Hearings in that case brought by 240 Bushmen are due to resume in February.
Meanwhile, Survival International itself has come under criticism over its statements.
"We object strongly to the fact that Survival International seeks to give the impression that they speak on behalf of all the Kalahari Bushmen when they handpick quotes from a few San only," said a statement issued in July from the Working Group of Indigenous Minorities of Southern Africa (WIMSA).
"We, the San from Botswana, Namibia, South Africa and Angola request SI to understand that the CKGR San do not want to close the door for negotiations with the Botswana government," it said.
South African diamond giant De Beers has also criticised Survival International for alleging that the resettlement of the Bushmen was to make way for diamond drilling in the game reserve.
The San is asking the court to
declare their eviction illegal
"Survival's confrontational campaign has alienated the government, divided the San and brought a halt to negotiations between the two," De Beers said in a recent statement.
Once numbering millions who lived freely in southern Africa, there are roughly 100,000 San left, with almost half of those - 48,000 - in Botswana, according to rights groups.
Survival International says the Bushmen's court case against the Botswana government is already the longest and most costly in Botswana's history, despite being brought by the country's poorest inhabitants.