Expelled ANC Youth League president Julius Malema was expected to address media in Sandton on Tuesday after he was denied entry to address mineworkers in Marikana.
"The press conference will...speak to the physical prevention of Malema from addressing mineworkers in Marikana despite the plea that he should come address them," suspended ANCYL spokesman Floyd Shivambu said on Monday in a statement.
"The press conference will make concrete reflections on the political developments in South Africa."
The briefing was expected to start at midday.
On Monday, police stopped Malema at the gates of Wonderkop stadium, where the workers had gathered to be briefed on developments about their wage demands.
After a lengthy discussion, Malema drove off, escorted by about 10 police vans.
A police helicopter circled above, while police on foot patrol ran to points of entry to stop Malema if he made any turns.