The vice-governor of China's Xinjiang region responded to international criticism of state-run detention camps on Tuesday by saying they were vocational centres which had helped to "save" people from extremist influences.

China had now effectively contained terrorism and religious extremism in Xinjiang, Vice-Governor Erkin Tuniyaz told the UN Human Rights Council.

Diplomats said his address was an effort to head-off any censure at the three-week session that began on Monday.

UN experts and activists say at least one million ethnic Uighurs and other Muslims are held in the detention centres in Xinjiang. China describes them as training centres helping to stamp out extremism and give people new skills.

"By setting up vocational education and training centers in accordance with the law, we aim to educate and save those who were influenced by religious extremism and committed minor legal offences," said Tuniyaz, who is an Uighur.

"This will prevent them from becoming victims of terrorism and extremism and to protect the basic human rights of the citizens from infringement," he said.

UN human rights chief Michelle Bachelet told the forum on Monday that she continued to raise issues related to Xinjiang, including "unfettered access" to the western region, and other matters with China.

Tuniyaz said freedom of religious belief is protected by law in Xinjiang, a multi-ethnic region of 25 million people where various religions coexist. But religious extremists have disseminated "sinister preachings" in Xinjiang, leading some to act like "drug addicts", he said.

" has placed fundamental interests of the people of all ethnic groups first, cracked down on violent terrorism crimes and emphasised taking preventive counter-terrorism measures and addressing the root causes of extremism, he said.

UN security was reinforced at the meeting, where Tuniyaz was accompanied by more than a dozen Chinese diplomats.

Sarah Brooks of the activist group International Service for Human Rights, told Reuters after the speech: "We should be clear that what is happening in Xinjiang is the wholesale destruction of a minority people and a culture, from the razing of religious sites to the separation of families, incentives for intermarriage, and the imprisonment of more than 350 academics and intellectuals."

Dolkun Isa, president of the exiled World Uighur Congress who led a protest in Geneva on Monday, accused China of "hiding the reality of what is happening to Uighurs".

"He (Tuniyaz) is not representative of the Uighur community"," Isa told Reuters.