The study by the Australian National University examined thousands of medical papers from China and unveiled the nation's clandestine organ harvesting trade.

Currently, harvesting organs from executed prisoners is legal in China.

However, this new research claims prisoners were operated on while still alive.

Human rights activists said the evidence "tells a terrible tale of murder and mutilation in China" and the stories coming out of the country are "almost too dreadful to believe".

The role of the study, which was published in the American Journal of Transplantation, was to establish whether a prisoner was classified as 'brain-dead' before their organs were removed for harvesting.

In 71 cases, "brain-death could not be declared", according to Chinese transplant records.

Matthew Robertson, PHD researcher and co-author of the report, said: "In these cases, the removal of the heart during organ procurement must have been the proximate cause of the donor's death."

"Because these organ donors could have only been prisoners, our finding strongly suggest that physicians in the People's Republic of China have participated in executions by organ removal", he added.

The surgeries were carried out on death row prisoners, as well as prisoners of conscience - people who are incarcerated for who they are or what they believe in, it has been claimed.

Mr Robertson and co-author Jacob Lavee, a cardiac surgeon, believe the true number of surgical deaths is much higher.

They claim the practice, which China has denied conducting, has been going on for three decades, with other organs such as livers and kidneys thought to be removed.

While waiting times for organ transplants in countries such as UK and US are measured in months and years, the waiting times in China are a matter of weeks.