Tibet's spiritual leader Dalai Lama (File Photo)

Bushmen in Botswana's Central Kalahari game reserve have written to the Dalai Lama, asking him to appeal to the government on their behalf for restoring their rights over ancestral lands during his upcoming visit to the African country.

Tibet's spiritual leader is expected to address a human rights conference in the capital Gaborone next week and also meet Botswana's president Ian Khama.

In a letter dated July 31, Bushman spokesman Jumanda Gakelebone asked the Dalai Lama to urge Khama "to listen to us and respect our rights".

Hundreds of Bushmen were evicted from their ancestral homelands in the name of conservation, and moved into government camps between 1997 and 2002, following the discovery of diamonds in the Kalahari desert.

Botswana's High Court ruled in 2006 that more than 1,000 San Bushmen had been wrongly evicted and should be allowed to return.

But the government continues to enforce a permit system, which rights group Survival International has compared to apartheid-era pass laws.

The Bushmen are also accused of poaching when they hunt to feed their families, and face arrests and beatings under a nationwide hunting ban, rights groups say.

"We still cannot live on our lands freely. The government makes it so that children must apply for permits to visit their parents when they become adults," Gakelebone said in the letter published by Survival International.

"Yet (the) government is happy for mining to take place on our ancestral land."

Calls and an e-mail to the Dalai Lama's office were not returned on Friday.

The United Nation's special representative on cultural rights in 2014 questioned why the San were evicted to conserve wildlife while diamond mining has been allowed to continue.

"No independent observer believes the Bushmen pose any kind of risk to the country's wildlife," said Survival International Director Stephen Corry.

"But they're still prevented from hunting, and still being forced to get permits just to see their relatives."

The visit of the Dalai Lama, who won the Nobel Peace Prize in 1989, has irked China, a major investor in Botswana, which regards him as a dangerous separatist.

"We are the first people of the Kalahari. We are the ones who have protected this land and the animals that live there," the letter said.