BERLIN, July 19 (Reuters) - Volkswagen (VOWG_p.DE) said it remained intent on commissioning an independent audit of its Xinjiang plant in China and was convinced that doing so would provide valuable insight, after some investors and activists criticised the mechanism as ineffective.

The United Nations and rights groups estimate that more than a million people, mainly Uyghurs and other Muslim minorities, have been detained in recent years in a series of camps in Xinjiang and used for low-paid and coercive labour.

China denies any human rights abuses in the western region.

"We are absolutely holding onto our intent [to run the audit]," Volkswagen said in response to an open letter sent by the Association of Ethical Shareholders Germany to the carmaker on the topic earlier in July.

"In contrast to you, we are convinced that an audit by an independent auditor can deliver important information about the human rights situation at the Urumqi plant," the statement, published on the website of the Business and Human Rights Resource Centre, added.

The shareholder association, which represents small investors on environmental, social and governance issues, had asked Volkswagen in its letter how it would ensure results were independent given heavy-handed censorship in the region and China's anti-espionage laws.

The carmaker did not directly address these concerns in its response, but said human rights were a key part of its behavioural code of conduct and that it adheres to the UN guiding principles for business and human rights.

"We have agreed high standards with our social partners at the Volkswagen Group which are mandatory," it said.