The most obvious option left for the ANC should Zuma decide not follow the party's directive for his recall would be to vote him out of office in a motion of no confidence.
The party's national executive committee met Monday to discuss Zuma's future in a meeting which lasted eight hours until the early of hours of Tuesday morning.
So far there has been silence from Zuma in response to Tuesday's ANC order, suggesting a power struggle behind the scenes with new party leader Cyril Ramaphosa.
The party wants Zuma to end his second five-year term early so that it can build up support ahead of 2019 elections.
The 75-year-old faces more than 780 allegations of corruption relating to a 1990s arms deal.
Finance Minister Malusi Gigaba however told CNN on Tuesday that Zuma was expected to announce his resignation at 10:00. Calls to ANC spokesman Pule Mabe's mobile phone didn't connect.
ANC chairman Gwede Mantashe told a meeting in the Eastern Cape province that the party had given Zuma an ultimatum to resign or face a motion of no-confidence, the Independent online news service reported.
Zuma then chose to fight back-and outrageously said he wanted three months' notice and guarantees about his future.
The ANC's "Top Six" officials including Ramaphosa approached Zuma at his Pretoria residence on February 4 to call on him to resign.
The party, once led by Nelson Mandela, has ruled South Africa since 1994, and led the country out of apartheid.
An elite police unit entered the compound of the Gupta family, which has been accused of using its connections to the president to influence Cabinet appointments and win state contracts. The Economic Freedom Fighters, the third biggest party, last month proposed the no-confidence motion that's now due to be debated on 22 February, and plans to go to court if it isn't brought forward.
If he refuses, Zuma would then likely be ousted via a parliamentary vote of no-confidence within days.
Sources said they also argued that "everyone in the movement did not agree with a recall".
In an interview with state broadcaster SABC, Zuma delivered a rambling monologue in which he denied any wrongdoing. He would make a statement later Wednesday.
Local media said this was to inform Zuma of the NEC's decision that he should leave office. He has emerged unscathed in a slew of no-confidence votes over the years despite the extraordinary number of corruption allegations against him, counting on the ANC's dominance in parliament to shield him.