The treatment of prisoners at Guantanamo bay could lead to human rights abuses by other countries, a leading campaign group has warned.

Amnesty International argued that the United States has created "unchallengeable executive power" for itself, subjecting detainees to a "parallel justice system" in which there were reports of mistreatment.

"The USA is on a slippery slope to promoting a world in which arbitrary unchallengeable detention becomes acceptable," said a spokesman.

"All too often where the US leads others follow. Increasingly by using the language of 'war', governments have disregarded human rights obligations.

"By using the term 'terror' they have endeavoured to avoid international human rights law.

"And by using the phrase 'war on terror' they have challenged the very framework of human rights and international humanitarian law."

"The USA has variously used hooding, blindfolding, handcuffing and shackling of detainees in Afghanistan, Guantanamo bay and Iraq," he added.

"The stark fact is that detainees held in Guantanamo bay, Bagram and elsewhere are at the mercy of the US government."

In its report, partially based on interviews with men released from the Cuban military base, the human rights group warned of the widespread use of tactics such as 24-hour lighting, sleep deprivation, inadequate exercise provision, stripping and blindfolding.

One man reported how he was made to stand for 10 days during questioning at Bagram.

"It will be a case of second-class justice for foreign nationals in violation of the prohibition on the discriminatory application of fair trial rights," the spokesman warned.

Amnesty International has demanded access to the prisoners, who they argue should be treated humanely and given access to lawyers.