The Health Ministry is required by law to keep details of former prime minister Najib Abdul Razak's medical treatment confidential.

Health director-general Dr Noor Hisham Abdullah said details can be furnished to the court should a court order be issued.

"The Health Ministry has to ensure confidentiality under the Medical Act 1971. Details on a specific patient can only be revealed to the court if ordered to do so," Noor Hisham wrote on his Facebook.

He said Najib was treated at the Kuala Lumpur Hospital (HKL) on Sept 12 after the former premier’s health condition became "tidak memuaskan" (unsatisfactory).