Beijing's denial "is quite predictable, with its pattern of answering UN questions in the past," Maya Wang, a senior China researcher for Human Rights Watch in Hong Kong, commented.
The UN committee's allegations are based on the findings of several reports, including one from activist group Chinese Human Rights Defenders.
While human rights campaigns in China do not have access to the camps, they have been able to speak to former detainees, with their families and with people who have left Xinjiang, Human Rights Watch says.
Groups Beijing classifies as "Chinese minorities" represent four to five percent of China's 1.4 billion population. The Uighurs, who are of Turkic and Muslim origin, number 11 million - 1.5 percent of the Chinese population - and live in the north-western region of Xinjiang, which in Chinese means "the new frontier".
The region is being increasingly populated by Chinese migrants, either sent by the government or moving by choice to find jobs. This has created tension, which has led to repression by the Chinese government.
"There is an anti Chinese terrorism which is directed against the harsh management of the so-called autonomous region of Xinjiang," explains Jean-François Di Meglio, president of the Asia Centre in Paris.
The Chinese Communist Party has justified increasingly tight policing of Xinjiang by saying it faces a threat from Islamic extremism and separatism. However, Maya Wang says repression goes far beyond security concerns.
According to the UN Committee's vice-chairwoman, Gay McDougall, the Chinese governement has given the committee a 100-page document in response to the UN allegations and has sent an invitation to the committee to visit Xinjiang and Tibet, another province where its handling of human rights has come under fire.