Former president Jacob Zuma looks down as he reads his resignation speech at the Union Buildings in Pretoria.
Zuma announced he had stepped down in a late-night television address in which he took some digs at the African National Congress (ANC) party that had threatened to oust him via a parliamentary no-confidence vote.
In a 30-minute speech, Zuma said he had "come to the decision to resign as president of the republic with immediate effect".
"I have only asked my party to articulate my transgressions and the reason for its immediate instruction that I vacate office," he said.
WATCH: President Jacob Zuma resigns
Ramaphosa, who won control of the ANC when he was elected as its head in December, is likely to be voted in by Parliament as South Africa&39;s new president on Thursday or Friday.
Political analyst Dumisani Hlophe said the inclination is that Ramaphosa is likely to appoint a woman as his deputy.
"My gut feel is that it&39;s likely to be a woman. My suspicion is it could be the likes of Lindiwe Sisulu or Naledi Pandor," he said.
"It wouldn&39;t make sense to put Nkosazana Dlamini-Zuma there simply because she contested."
Hlophe said many MPs are likely to face the chop.
Political analyst Khaya Sithole told eNCA&39;s Dan Moyane that Ramaphosa must reshuffle the cabinet to start on a clean slate.
Sithole said he thinks Lindiwe Sisulu is the obvious choice for a deputy president.
- Additional reporting AFP