Amnesty International has asked its network of health professionals to appeal to Prime Minister Abdullah Ahmad Badawi to allow the country's jailed former deputy premier to seek medical treatment of his choice for a critical back surgery.

Anwar Ibrahim, considered a political prisoner by human rights groups and the United States, has spent more than five years in jail, having completed a sentence for corruption, and is currently serving a nine-year term for sodomy.

He was rushed to hospital last month from prison due to complications from a damaged spinal disc which he said was aggravated by a police beating after his arrest in 1998.

Amnesty, in a letter to health professionals linked to its global network, asked them to write to Abdullah "expressing concern" over reports of Anwar's impaired heath and urging the authorities to allow Anwar "to exercise without restriction his right to seek medical treatment of his choice."

The rights group also advised them to express "grave concern" to Abdullah that the charges laid against Anwar "were politically motivated" and called for his immediate and unconditional release, according to a copy of the letter received by AFP on Thursday.

Doctors have advised Anwar to undergo surgery soon, but he is pressing to be allowed to go to Germany for the operation - a plea which the government has so far refused.

"We are extremely concerned about the reported deterioration of Anwar Ibrahim's health. His health, including his kidney, could be permanently damaged, said T Kumar, Amnesty's Washington-based advocacy director for Asia and Pacific.

Just leader

By considering Anwar's plight, Abdullah could "show to Malaysians and to the whole world that he is a reasonable and a just leader and above petty politics," Kumar said.

Former prime minister Dr Mahathir Mohamad sacked his deputy in 1998 and Anwar was later jailed on charges he says were trumped up to prevent him from making a challenge for the premiership.

The conduct of the corruption and sodomy trials were widely condemned internationally.