Spain's top investigating judge Baltasar Garzon is to probe suspected torture and ill-treatment of inmates at the US prison of Guantanamo Bay, the daily El Pais has reported.

The paper reported that Judge Garzon would be acting on complaints lodged by a number of associations, focussing on one prisoner, Ahmed Abderraman Hamed, who has Spanish nationality.

Three other detainees, Moroccan Lahcen Ikasrrien, Palestinian Jamiel Abdulatif al-Banna and Libyan Omar Deghayes would also be concerned as they had links with Spain, El Pais said.

In 2005, Spain declared itself competent to investigate any crime committed abroad, but after diplomatic problems the scope of the inquiries was reduced in 2009.

Spanish courts can now deal only with cases that have a clear link with Spain, or cases that are not being investigated in countries where the offences are alleged to have been committed.

El Pais said Washington had not replied to a request made seven months ago from Madrid as to whether it was investigating the allegations now being taken up by Garzon.

The Palestinian Authority's foreign minister Riyad al Malky said in Madrid last week that Spain had agreed to accept a Palestinian Guantanamo Bay detainee.

The unnamed man will be transferred to Spain in early February along with another man whose nationality has not been confirmed, according to press reports quoting Spanish diplomatic sources.

US President Barack Obama has promised to close the controversial prison camp for terror suspects in a US enclave on Cuba, and the United States has started to slowly empty it of detainees.