Dr. Chumsak Phruksaphong, deputy secretary-general of the Medical Council, said the investigation was launched after a former doctor at the hospital filed a complaint alleging that relatives of terminally ill patients were pressured to sign documents donating organs.
Thai newspapers reported that the doctor also alleged organs were being sold by the hospital to patients in need of transplants, a practice that is illegal in Thailand.
Neither the hospital nor any of the doctors involved were identified.
"If the case is real, the wrongdoer will face a criminal charge of murder and stealing, as well as cancellation of his medical license," Chumsak said at a news conference.
The mass-circulation Thai Rath newspaper carried a story this past weekend saying the hospital, located in Samut Prakan, near Bangkok, had tricked the father of a motorcycle accident victim into signing papers approving the removal of his daughter's kidneys.
The father, Charoen Deeyotha, was quoted as saying he thought he was signing a waiver for an operation and would not have given consent for organ removal. When she died and her body was recovered for the funeral, it had been cut open from the chest to pubis, Thai Rath said.
Instead of charging him for the medical care, the hospital gave Charoen 100,000 baht ($2,770 U.S. dollars) as an educational fund for his grandchildren.
Thai Rath's story said the incident raised suspicions that the accident victim was allowed to die on purpose.
Chumsak said that such reports were causing panic among people who planned to donate their organs.
He said a panel established by the Medical Council to investigate the issue should complete its work in two months.
Chumsak said that while regulation of the donation and transplant of organs is very strict in Thailand, there is a severe shortage of human organs.
Only 10 percent of patients needing new kidneys are able to obtain them after waits averaging more than a year, he said.