The group, led by Angkhana Neelaphaijit, wife of missing Muslim lawyer Somchai Neelapaichit, will point out the failure of Thaksin government to protect human rights and single out its policies that have aggravated human-rights violations.

Annan arrived in Thailand yesterday as a guest of the government to present the United Nations Development Programme's Human Development Lifetime Achieve-ment Award to His Majesty the King. He will leave the country on Saturday.

The case of Somchai, who was abducted in March 2004 and is presumed dead, has been under the close attention of UN agencies.

The group will deliver a report to the UN secretary-general about human-rights violations in Thailand's three southernmost provinces, where insurgent violence has killed more than 1,000 people, and the enforcement of a state of emergency that allows police to arrest and detain suspects for as long as 30 days.

It says that when first detained, suspects are not allowed to see outsiders, except for their families, and are not allowed to meet lawyers. They are not told how long they will be detained, which increases the risk they will mysteriously disappear or their rights will be further violated.

The group will also point out that the government has failed to show progress in investigating the deaths of 2,598 people killed during the "war on drugs", from February to April in 2003. Human-rights activists who are opponents and critics of the government have also been threatened and intimidated.

The group will also say that the Thaksin government, which came to power in 2001, has oppressed the freedom of the press through intimidation, cancelling of concessions or advertising contracts and filing of libel suits.

The group includes Amnesty International Thailand, the Students' Federation of Thailand, non-governmental organisations, academics and senators.