The South African Police Service has declared all marches in Tshwane on Friday as illegal.
Acting police commissioner Khomotso Phahlane on Thursday said anyone taking part in these would be breaking the law of the country.
He said the organisers do not have permission.
"All protest action in Tshwane will be illegal as no approval has been granted by relevant authorities," he said.
Several marches and events, mainly in reaction to President Jacob Zuma's Cabinet reshuffle, are expected to take pace nationwide on Friday.
Save SA meanwhile said its march to the Union Buildings has been granted permission to go ahead, a spokesperson said on Thursday evening.
"We had our lawyers file an urgent application with the chief magistrate, setting out our efforts to obtain permission. She considered the application and overturned the prohibition. We are waiting to get the papers in the next few minutes," Save SA spokesperson Mark Heywood told News24.
He said the organisation followed all procedures to get permission for the march to call for President Jacob Zuma to step down.