"The ANC has decided to recall the president of the republic before his mandate has expired," Gwede Mantashe, the ANC secretary-general, said after a meeting of the party leadership.
"Our decision has been concluded, and the formalities are now subject to the parliamentary process," Mantashe said.
"We have communicated our decision [to Mbeki] and that we will be going through parliamentary process. He has agreed to participate in that process."
Mantashe said the decision to ask him to stand down was taken in the interests of party unity.
"This is not a punishment," he said. "We decided to take this decision in an effort to heal and reunite the ANC."
|Mantashe said formalities for Mbeki to quit await parliamentary approval [AFP]
Themba Maseko, the government spokesman, told AFP news agency that a special cabinet briefing would be held on Sunday afternoon, hereafter Mbeki would "speak to the nation" in an address broadcast live on radio and television.
A court on September 12 threw out corruption charges against Zuma, alleging that Mbeki's government had interfered in the decision to prosecute him, claims Mbeki's cabinet has denied.
After the ruling, there was intense speculation over whether the ANC would ask Mbeki to quit, push him out in a vote of no confidence or allow him to serve out his term of office.
Al Jazeera's Bernard Smith, reporting from Johannesburg, said "it looks like the beginning of the end for Thabo Mbeki".
He quoted Mantashe as saying that when the party told Mbeki what it had decided, his reaction was normal and that he did not display any shock or any depression.
Mbeki agreed that he was going to take part in the processs to remove him as president, Smith said quoting Mantashe.
"It seems like Mbeki is not going to fight this," Smith said.
"It looks like he is going to end up resigning and then parliament will appoint a new president who will be in place until scheduled elections are called as early as April - between April and June - next year."
The ANC appeared unable to reach a decision on the issue at a meeting on Friday and cancelled a news conference where officials had been scheduled to announce their decision.
"The debate is actually in the middle of nowhere. Everybody is expressing their view and then when we complete that debate and take a decision we will come and communicate with you," Mantashe said.
After the ruling in Zuma's trial, the ANC youth league called for Mbeki to leave but the ANC as a whole reacted more cautiously, saying any decision would be by consensus and announced after its national executive committee had met over the weekend.
Half the cabinet is reportedly threatening to walk out if Mbeki is forced to leave.
Mbeki issued a statement on Friday saying: "It impoverishes our society that some resort to the tactic of advancing allegations with no fact to support these.
"The question will have to be answered now - what kind of society are we building, informed by what value system and with what long-term effect to the political and overall moral health of the nation?"
The dismissal of corruption charges against Zuma makes it possible for him to become South Africa's president after next year's election.