"We have now asked the chief whip to proceed with the motion of no confidence tomorrow in parliament... so that President Zuma is then removed," ANC treasurer-general Paul Mashatile told reporters Wednesday.
He said parliament, where the ANC has a large majority, would then "proceed to elect (Cyril) Ramaphosa as president of the republic."
Zuma was expected to respond later on Wednesday to the ANC's order for him to resign.
"For us, as the ANC leadership, we can no longer wait beyond today," Mashatile said.
"We don't want to keep South Africa waiting. If President Zuma at some point will respond he will respond, but we can't continue waiting. The decision has been taken and must be implemented."
The power struggle over Zuma's departure has put him at loggerheads with deputy president Cyril Ramaphosa, his expected successor, who is the new head of the ANC.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)