The group of 152 were arrested in mid-November and detained at the Immigration Detention Center (IDC) in the border city of Nong Khai.

Most of them have already been recognized as refugees by the UN High Commissionerfor Refugees (UNHCR).

"Lao officials have been allowed to interview and photograph members of the group... in Nong Khai, to verify that they are Lao nationals, preparatory to returning them to Laos," Amnesty said in a statement.

"Three buses are reportedly parked outside the IDC ... ready to transport them."

Laos foreign ministry spokesman Yong Chantalangsy confirmed the planned repatriation but said he could not say when it would take place.

"We are in the process of identification," he told AFP.

"This is part of the process by the two countries to solve the Hmong issue. We will take back those who were caught entering Thailand illegally and proved to be Lao nationals."

UN High Commissioner for Human Rights Louise Arbour last month condemned the repatriation plan, warning the 152 Hmong -- including 85 children -- were risking persecution.

According to Amnesty, "in Laos the group would be at risk of severe human rights abuses, including torture ... No international human rights organization would have access to the group in Laos to monitor their well-being."

Yong denied the accusations, saying the Hmong would eventually be taken back to their families. But he confirmed no third party would be allowed to monitor the process.

He also said there were no grounds for their UNHCR refugee status.

"There is no war, there is no conflict, there is no violence, there is no genocide," Yong said, adding the UNHCR "would have some problems justifying their decision".

Bangkok announced last month week it intended to repatriate more than 6,500 members of the Hmong ethnic minority, including the 152 who were detained by police.

Some Hmong, a hill tribe people, were allied with the United States during the "Secret War" in Laos that was part of the wider Vietnam conflict.

Some have fled persecution in communist Laos while others, particularly in more recent times, have sought to escape rural poverty.

Laos has said it would accept refugees who can prove their Lao nationality but refused the intervention of a third party in the transfer. Bangkok has so far asked for international supervision of the process.

Agence France-Presse