0327 GMT February 20, 2018
Zuma, in power since 2009, is fighting for his survival and faces the imminent risk of being ousted from office by his own party after multiple graft scandals, AFP reported.
The African National Congress, which has ruled since Nelson Mandela won the post-apartheid 1994 election, is divided over whether Zuma should be "recalled" from his position.
As president, Zuma had been due to deliver the State of the Nation address to Parliament in Cape Town on Thursday.
But the party's national executive committee, its highest decision-making body, will hold a special meeting today to discuss his possible removal.
"We thought that we needed to create room for establishing a much more conducive political atmosphere in Parliament," Parliament Speaker Baleka Mbete told reporters.
"When we met the president this afternoon, we then learnt that he was already writing to Parliament to ask for the postponement.
"A new date for the state of the nation address will be announced very soon."
The 80-member ANC committee meeting today could "recall" Zuma from office — an instruction he could constitutionally refuse to obey, triggering political chaos.
ANC Deputy Secretary General Jessie Duarte told reporters that senior party officials had discussed Zuma's future on Monday.
"It was discussed at a great deal of length. I can say to you that there are different views," she said.
Many ANC members are pushing for Cyril Ramaphosa, the new head of the party, to replace Zuma, 75, as president immediately.
But Zuma loyalists have said that the serving president should complete his second and final term in office, which would end when elections are held next year.
Duarte confirmed that if Zuma resigned, Deputy President Ramaphosa would automatically take office.
"What we are hoping for is that the NEC (national executive committee) will emerge with a united view on this matter," she said.
The power struggle has rocked the ANC, the much-celebrated liberation party that led the fight against white-minority rule but which has since lost much of its public support.