Pakistan's leading rights watchdog on Friday expressed concern at the denial of due process to Shakeel Afridi, the doctor who was given a 33-year prison term for allegedly helping the CIA track Osama bin Laden before he was killed last year.
The Human Rights Commission of Pakistan demanded that Afridi "must get a fair trial" irrespective of the charges against him.
"One is concerned about the security of the country, but that cannot be made the basis of denying rule of law to anyone," the organisation said in a statement.
The HRCP expressed concern that Afridi's trial fell "well short of the due process standards on many counts, not least because the core principle of natural justice has been ignored and Afridi denied due legal assistance".
It said the question of trying him for treason too was controversial.
"His actions may well have been prompted by the declared policy of the state to fight all forms of terrorism in sincerity. Irrespective of the charge against him, there was no reason for trying Afridi in a tribal court, when the supposed offence had taken place in Abbotabad, nor for denying him a public trial or legal assistance of his choice," the statement said.
According to media reports, Afridi ran a fake vaccination campaign in Abbottabad town of Khyber-Pakhtunkhwa province in a bid to obtain DNA samples of bin Laden's family.
He was arrested shortly after bin Laden by killed in a unilateral US raid on May 2 last year.
On Wednesday, a court in the Khyber tribal region convicted Afridi under the harsh British-era Frontier Crimes Regulation and gave him a 33-year prison term under provisions of the Pakistan Penal Code related to treason.
Rights groups and legal experts have criticised the verdict as Afridi was not represented by a lawyer during the trial.
The HRCP said: "Such treatment has given rise to perceptions that the only reason he was tried by a tribal court was to deprive him of the rights guaranteed under the constitution of Pakistan.
"HRCP calls upon the government to ensure that Afridi gets a fair trial and is afforded an opportunity to defend himself against the charge brought against him".
Afridi was treated by doctors after he fainted at the Central Jail in Peshawar, where he is being held.
Officials said he was in poor health. Afridi is being kept away from other prisoners to avert any danger to his life, the officials said.
The US administration has criticised the conviction of Afridi, and Secretary of State Hillary Clinton described his treatment as "unjust and unwarranted".
"The US does not believe there is any basis for holding Dr Afridi. We regret the fact that he was convicted and the severity of his sentence," she said.