The Cambodian Permanent Mission to the UN Office in Geneva has dismissed "groundless allegations" by four UN special rapporteurs regarding the detention of an activist who they said suffered from autism.

The rejection came after the UN experts issued a joint statement on September 2 calling on Cambodia to release the 17-year-old, who was arrested on June 24 and has been charged with incitement and insulting public officials in connection with his online activities.

They alleged that the man had autism spectrum disorder and had been held in pre-trial detention for more than two months without access to his family.

The UN officials – Vitit Muntarbhorn, special rapporteur on the situation of human rights in Cambodia; Irene Khan, special rapporteur on the promotion and protection of the right to freedom of opinion and expression; Tlaleng Mofokeng, special rapporteur on the right to health; and Mary Lawlor, special rapporteur on the situation of human rights defenders – noted that the teen's father was a former opposition official and his mother a human rights defender.

“This case is particularly disturbing because the UN Convention on the Rights of Persons with Disabilities – to which Cambodia is also a party – requires authorities to consider the best interests of children with disabilities and provide appropriate assistance,” the experts said.

“We strongly appeal to the Cambodian government to release this child and to ensure that his human rights are protected in line with the principle of the best interests of the child in compliance with the Convention on the Rights of the Child, the Convention on the Rights of Persons with Disabilities and Cambodian law,” the experts said.

The Permanent Mission said the rapporteurs' claims were misleading and politically motivated.

It said making a reference to the political background of the accused’s family was indicative of their attempt to politicise the issue.

“In the Kingdom, individuals are charged on the basis of law-prescribed offence rather than who they are. With corresponding concrete evidence, these charges are fully in line with articles 494, 495 and 502 of Cambodia’s [Criminal] Code, crafted with the help of Western experts,” the mission said.

It continued that Cambodian courts heard the case based on concrete evidence, including medical certificates proving specific health conditions, not hearsays. All charges and procedures are in full compliance with the laws.

“The special rapporteurs’ demand for the government to release anyone is tantamount to an affront to power separation and independence of the judiciary, guaranteed under the Constitution, and to national sovereignty,” it said.

It said the UN experts have "professional negligence" in duly cross-checking the sources of information.

The special rapporteurs, it said, have never encouraged a distinction between free speech and hate speech. Their approach deviates from that of the UN secretary-general Antonio Guterres, who has stressed that fake news and hate speech constitutes an attack on the essence of human rights norms and principles.

The permanent mission urged the special rapporteurs to strictly adhere to the Code of Conduct and Manual of Operations of the Special Procedure Mandate Holders.

“Only with such cautious and due diligence to the said protocols will enable states in general and Cambodia in particular to maintain the trust and cooperation with this mechanism,” it said.