Observers said the interest from wealthy Chinese may be because they are worried about bans on burial in favour of cremation in many places.

Traditional Chinese culture rules that the body must be intact to prepare for the afterlife.

Professor Huang Wei , a historian at Sichuan University in Chengdu , said: "Chinese people have always been interested in body preservation and life extension. Cryonics is a new option from the West which will certainly interest those who can afford it."

Cryonics involves storing bodies in aluminium containers in super-cold liquid nitrogen.

Blood circulation is maintained by life-support equipment immediately after death and then 60 per cent of the water in the body's cells is replaced by a chemical preservative to prevent destructive ice forming in the body in subzero temperatures.

The service costs at least US$200,000 for whole body preservation, with extra fees for members from countries outside the US - including China.

Marji Klima, an administrator at the Alcor Life Extension Foundation, said its door was open to more members from China.

"There have been discussions with some citizens from China recently who would like to start a team in China," she said.

There were no definite plans, but it was "technically possible to extend our service to China".

Andy Zawacki, the chief operations officer at the Cryonics Institute, said it too was attempting to woo Chinese customers.

"We are currently working with a group of people from China to establish a network of standby providers so that they can prepare our patients in China and have them transported to our facility for long term storage," he said. "So far this is just in the planning stages, but we hope to be able to offer the services to people in China."

A businessman in Guangdong said he was considering the service for himself and his family. He said his biggest motivation was not the hope of future technology bringing him back to life, but the central government's policy on forced cremation.

Apart from some ethnic minorities, most Chinese citizens are required by the authorities to be cremated to reduce the size of graveyards and conserve land for food production.

"In my hometown almost everyone loathes the cremation policy," he said. "In our culture it is very disrespectful to the dead."

He said cost was not an issue for him in terms of cryonics, but he feared Chinese customs may prevent shipping a body overseas for storage.

"I have confidence that they can carry out the preservation that they promise. If I or my family can be revived and reunited in the future, it would be a bonus," he said.

Xu Shaozhou , a sociology professor at Wuhan University who has studied burial traditions in China, said that if the government did not relax the forced cremation policy more rich Chinese might consider cryonics.

Cremation had never been accepted by mainstream Han Chinese culture over thousands of years and forced cremation in recent decades had prompted social conflict, he said.

"The existing cremation policy has many problems and the social and environmental cost of it may far exceed the so-called benefits," said Xu.

Professor Huang at Sichuan University said there was a long history in China of the rich and powerful becoming preoccupied with the possibility of an afterlife, with emperors building huge tombs to prepare for it.

"The richer and more powerful the nation became, the more the elite engaged in the pursuit of immortality," he said.

However, a scientist cautioned against investing too much faith in cryonics.

Zheng Congyi , a professor of biology at Wuhan University, said no humans or animals had been brought back to life using the procedure.

"Today we can [use] technology to revive a cell, but the procedure gets much more difficult, if not impossible, with increased number of cells," he said.