SABC station managers have been ordered in a secret memo to avoid broadcasting programmes involving "political discourse", citing the arms deal row, in the run-up to next year's election.
The memo said the decision had been taken against a background of discussion of corruption allegations against Deputy President Jacob Zuma.
The Broadcast Electronic Media and Allied Workers Union vowed to take the SABC to the Broadcasting Complaints Commission, accusing it of trying to gag presenters and prevent debate on Zuma.
Issued last week by Judi Nwokedi, the SABC's managing director of public broadcasts, the memo said all programmes, content and talk shows that involved "political discourse" should be "avoided absolutely".
Addressing station managers as "Dear Team", the memo reads: "As you are aware, we are heading into the campaign phase of election 2004. This means that various attempts for political jostling will be made by politicians across the country.