The former president has been expelled from the ruling ANC and has been campaigning for the newly formed MK party. An MK spokesman said the party will appeal the decision made by the Independent Electoral Commission.
Former South African President Jacob Zuma has been disqualified from running in the country's general elections in May.
The Independent Electoral Commission (IEC) said on Thursday he was one of eight candidates who faced official objections.
"In the case of former president Zuma, yes, we did receive an objection, which has been upheld," IEC chairperson Mosotho Moepya said at a media briefing.
The IEC disqualified him over his 2021 conviction and jailing for contempt of court.
Increasing tensions in the run-up to the polls
Zuma, who led the country from 2009 to 2018 until his removal amid wide-ranging allegations of corruption, parted ways with the ruling African National Congress in December and is now leading the newly formed uMkhonto weSizwe Party (MK).
MK spokesman Nhlamulo Ndlhela told the AFP news agency the party " of course will appeal" the IEC's decision.
Some of the party's leaders have previously threatened violence if Zuma was barred from contesting the elections.
Seperately the ANC has launched a legal challenge against Zuma's party, disputing its use of the name and trademark of the dissolved organization.
The MK party is named after the former military wing of the ANC, which was disbanded at the end of apartheid.
MK party can still compete in the vote
The IEC's decision does not prevent the MK party from taking part in the May 29 poll.
It is widely expected to be the most competitive vote since the advent of democracy in South Africa in 1994.
According to recent polls, the ANC may dip below 50% of the national vote for the first time since it came into power.
Zuma's popularity has helped the MK Party gain traction ahead of the upcoming polls, particularly in his home province of KwaZulu-Natal.
lo/wd (AFP, AP)