Media reported that the Chinese Red Cross demands money from hospitals to help arrange organ donations.
The fee charged by the state-run body varied by location and went mostly to pay donors' medical costs, a Red Cross Society of China official told the Beijing News.
It cited a hospital employee in the southern city of Guangzhou as saying the average donation for obtaining an organ was 100,000 yuan ($16,000).
"But exactly how this money is used, the public does not know," the employee said.
Another hospital employee in the eastern province of Jiangsu said it gave the Red Cross 50,000 yuan intended for the donor's family.
Ethical considerations are a key issue in many transplant programmes around the world, and under Chinese law it is illegal to trade in organs or to receive money for donations.
Demand for transplants in the country is high, with a vast and ageing population. But supply is low because many Chinese believe they will be reincarnated after death and so feel the need to keep a complete body.
Only one in 30 patients registered for an organ transplants receives one each year, the Global Times said Tuesday, citing the National Health and Family Planning Commission.
The shortfall opens the way to forced donations and illegal sales, while China still collects organs from executed prisoners, although it has repeatedly said it will stop doing so.
A new system in 2010 aimed to make transplants fairer and more open, but a year later it was used in only a third of operations, the China Daily reported last month.
Chinese Red Cross officials were not immediately available to comment to AFP.
The Shenzhen chapter of the Red Cross denied the Beijing News report in a statement to the official Xinhua news agency, saying it had worked on 25 organ donation cases with a hospital that decided to donate a lump sum of 150,000 yuan for donors.
There was no "100,000 yuan per case" arrangement, Xinhua quoted the statement as saying.
The China Red Cross previously faced accusations of a lack of accountability over 80 million yuan raised from works donated by artists for victims of the Sichuan earthquake in 2008.
State auditors have raised questions over discrepancies in its budgets, which it has insisted were not the result of corrupt practices.