An AWB flag was found hoisted in place of the South African national flag at the Ventersdorp hospital on Friday, the North-West health department said.
The province's Health MEC Magome Masike came across it during an unannounced hospital visit, said spokesman Tebogo Lekgethwane.
He said security guards were meant to hoist the national flag onto the pole every morning, to be taken down at night.
“We believe somebody took out the South African flag and put up this one. It's unknown how they did it because the hospital has 24-hour guards, Lekgethwane said.
“Our impression is that someone is trying to send a message to us... it's difficult to understand what the message is right now.”
The police had been alerted and the matter was being investigated.
“The MEC is still questioning hospital management. So far they say the last time they saw the national flag hoisted was yesterday,” Lekgethwane said.
The hospital did not have security cameras.
Afrikaner Weerstandsbeweging leader Steyn van Ronge could not immediately be reached for comment. – Sapa