The Hong Kong-based AHRC described Surakiart's candidacy as a threat to the global human-rights movement.

The commission denounced the Thai government's support for Surakiart's campaign as "immoral and dishonest".

This follows a UN report saying the Thai government's granting of immunity for security forces engaged in "counter-insurgency" efforts in the South violated the government's obligations under international human-rights law.

In an open letter to Surakiart, AHRC chief Basil Fernando asked: "What are your qualifications to be UN secretary-general, deputy prime minister?"

Fernando said that since Surakiart became foreign minister in 2001 and deputy prime minister in 2005 his government had failed to join a key international rights treaty, despite saying it would do so. It also failed to implement the suggestions of a treaty body on human rights, and failed to cooperate with UN rights experts.

On the other hand, it noted that Surakiart had "chastised journalists in Thailand for reporting on gross abuses" there which might undermine his candidacy.

"You would have to admit that for someone trying to become the secretary-general of the United Nations this record of involvement with the UN and its agencies is not very good, is it?" Fernando said.

"In fact, it is better characterised as persistent non-involvement and deliberate negligence," he said.

The AHRC pointed out that Thailand's worsening rights record had led it to unsuccessfully seek a seat on the new UN Human Rights Council.

"This man has had direct responsibility, through his capacity as the country's leading diplomat, for dealing with the UN and seeing that Thailand would become a more active member of the international human-rights community," Fernando said.

"But his government has treated UN rights treaties, bodies and experts with disdain.

"He has remained silent and inert on all key rights issues affecting his own country and indeed those of the Asian region, and we expect that were he to become secretary-general this silence would almost certainly continue and spread," he said.

The AHRC said that it felt "compelled" to speak out against Surakiart's candidacy lest it be forced to share the blame from people in other parts of regions were he to be elected and "make a misery of the lives of people in other countries in addition to his own".