Even when detainees are released, they may die of their injuries, be scarred for life mentally or physically and not be able to afford medical treatment or be denied it completely, the Free Tibet group said.
"Despite claims by the Chinese government that there are 'extremely few cases of torture', the evidence tells a different story," Free Tibet director Stephanie Brigden said. "There is no doubt that the Chinese government is permitting the use of torture as a weapon to suppress the Tibetan people."
China's Foreign Ministry did not immediately respond to a request for comment and calls to the spokesman's office of the Chinese-run Tibetan government in Lhasa went unanswered.
Chinese troops marched into Tibet in 1950 and the region's spiritual leader the Dalai Lama fled into exile in 1959 after a failed uprising against Beijing's rule.
Mountainous and remote Tibet was rocked by anti-Chinese protests earlier this year, which China blamed on the Dalai Lama, whom it brands a separatist. He has repeatedly denied the claims.
Free Tibet said it had profiled numerous cases of torture carried out against people detained following the demonstrations, which spilled over into other ethnically Tibetan parts of China such as Gansu, Qinghai and Sichuan provinces.
It said that one monk at the Labrang monastery in Gansu, Jigme Gyatso, had to be hospitalised for almost a month after his injuries received in detention.
"They would hang me up for several hours with my hands tied to a rope ... hanging from the ceiling and my feet above the ground. Then they would beat me on my face, chest, and back, with the full force of their fists," he said in the report.
"Finally, on one occasion, I lost consciousness and was taken to hospital. After I regained consciousness at the hospital, I was once again taken back to prison where they continued the practice of hanging me from the ceiling and beating me."
China has vowed to stamp out torture in its judicial system, described as widespread by some critics, in the face of international and domestic pressure.
Last month, the U.N. Committee Against Torture, in a rare public review of China's record, expressed dissatisfaction with a "very serious information gap" about abuses in the country where criminal justice information is often considered a state secret. Free Tibet, in the report issued to coincide with International Human Rights Day, said Chinese laws aimed at protecting detainees were regularly ignored in Tibet.
"The international community can no longer hide behind sound bites condemning China's human rights track record in Tibet and must now take specific actions to reverse the worsening crisis in Tibet," Brigden added.
China and envoys of the Dalai Lama have been meeting on and off for the past few years, but with little to show for their talks.
Beijing has rejected the Dalai Lama's calls for greater autonomy as being part of a plot for covert independence.
On Wednesday, the semi-official China News Service quoted Si Ta, a deputy head of the United Front Work Department which handles relations with non-Communists and ethnic and religious minorities, as repeating that the door to talks was always open.
"The Party still has expectations of the Dalai Lama and plenty of patience, but 'Tibet independence', 'half independence' or 'covert independence' are unacceptable," it paraphrased him as saying in Washington.