Patients from Bheki Mlangeni District Hospital in Soweto, Gauteng have been moved following a fire at the hospital's administration block on Monday morning.
They had to be evacuated from the facility after the fire broke out at around 06:30, the Gauteng Health Department said.
Spokesperson Lesemang Matuka said the fire was contained at around 08:00 by the Johannesburg Emergency Services.
No patients were injured and the 86 in-patients have been moved to various neighbouring healthcare facilities, he said.
"All patients in the hospital were safely evacuated and some have already been transported to facilities such as Chris Hani Baragwanath Academic Hospital, Southrand Hospital, Rahima Mother and Child, Sterkforntein and Lenasia South District Hospital," Matuka said.
He said the hospital is not admitting any patients at present. The department has asked the public to use other healthcare facilities in the vicinity until "further notice".
Staff will also not be at the facility until it is deemed safe to return.
The cause of the blaze is still unknown and the department is probing and conducting an assessment on the damages.
Bheki Mlangeni District Hospital was opened in 2014 and has 3 900 beds.