The Corrections Department on Monday said it cannot give details about inmates' health or other medical details without their consent, to protect their right to privacy.
The statement comes amid continuing calls for the department and the police to release updated details on the health of convicted former prime minister Thaksin Shinawatra, who has been in the Police General Hospital since shortly after his sentencing more than a month ago.
There are suspicions Thaksin, who has a year-long sentence to serve, is being given privileged treatment in being allowed to stay out of prison.
His daughter Paetongtarn said last week that her father had undergone surgery since arriving back in Thailand and was recovering, but she gave no further details.
The Corrections Department said it must comply with human rights protections and related laws, which treat health information as confidential. It could not disclose inmates' health details without their consent.
Political activist Srisuwan Janya has demanded the department disclose an official report by corrections officials guarding Thaksin at the hospital.
According to Mr Srisuwan, the officials' daily report to their supervisor and the department chief is a detailed record of what happened that day, and includes information about meals and visits and is considered official information.
He said the report is not about Thaksin's medical condition, and he had the right to access it under the Official Information Act of 1997.
