Holomisa told a crowd of 200 supporters outside the ANC's head office in downtown Johannesburg that he would be challenging his expulsion in the Supreme Court.
Asked if he had been formally told of his expulsion, Holomisa said he had not, but he knew that this was the case.
Supporters of the former deputy environmental affairs and tourism minister included about 30 heavily-armed members of the Elias Motsoaledi branch of the SA Communist Party.
The former Deputy Environment minister Bantu Holomisa, whose expulsion from the ANC was upheld on Monday morning by the National Executive Committee, will apply to the Rand Supreme Court for an urgent interdict to suspend the effect of the party's ruling while he seeks relief from the courts.
Speaking after his appeal to the NEC on Monday, Holomisa told Sapa he would meet his attorneys at 3pm and they would seek an interdict against the ANC either later in the afternoon or on Tuesday.
This would mean he would remain an ANC member and MP until such time as the Supreme Court ruled on the issue, he said.
Although he had not been formally informed of his expulsion, sources had indicated that the route decision had been unanimous, Holomisa said.
The 77-member NEC, including President Nelson Mandela, Deputy President Thabo Mbeki and ANC cabinet ministers, were still deliberating reasons for upholding the expulsion.
The appeal - a month after the national disciplinary committee's decision to expel him for misconduct and bringing the ANC into disrepute - was heard during a special NEC meeting, ostensibly to discuss constitutional and other organisational issues.
The next NEC meeting was scheduled only for November.
The interdict bid marks the first step in Holomisa's bid to seek relief from the courts, after exhausting all avenues of internal appeal within the party.
Holomisa said the NEC's decision showed that members did not care about procedure.
He was impressed with the questions asked. Most of these had been put by Mineral and Energy Affairs Minister Penuel Maduna, and he had been given ample time to put his case.
He had been asked to leave the meeting at the ANC's Johannesburg headquarters while members deliberated.
The political implications of upholding his expulsion had apparently been raised, particularly by Mpumalanga premier Mathews Phosa, while certain NEC members were initially in favour of a lesser penalty.
Holomisa, who received the most votes in the last NEC elections, has widescale support, particularly in the Eastern Cape and Gauteng.
Several of his recent rallies had huge turnouts, despite an ANC instruction to provincial members not to attend.
Holomisa said that, according to reliable sources, disciplinary committer chairman Kader Asmal had moved a motion that the expulsion be upheld and that this had been unanimously agreed to.
The former Transkei military leader said: "I will be dealing with a court and all my fears about unfairness and prejudice will be put to rest."
Holomisa said he had been asked whether any NEC members should recuse themselves, but that he believed this would be futile as the entire body had already been influenced by members of the National Working Committee.
He believed that the decision to expel him had already been taken at a meeting of senior NEC members at President Nelson Mandela's Houghton home in Johannesburg on the eve of his appeal.
"My appearance was a mere formality," Holomisa said.
ANC chairman Jacob Zuma told a media briefing at the party's head office in Johannesburg: "The NEC ... after due consideration unanimously confirmed the findings of the national disciplinary committee and upheld the sentence passed."
The disciplinary committee on August 30 found Holomisa guilty of bringing the party into disrepute by a remark to the Truth and Reconciliation Commission that Public Enterprises Minister Stella Sigcau accepted a R50,000 payment from former Transkei ruler Chief George Matanzima.
The R50,000 was reportedlky part of a R2 million payment to Matanzima by hotels magnate Sol Kerzner.
The payment was investigated by the Alexander commission appointed by Holomisa when he was military ruler of Transkei. The commission said it accepted Sigcau's explanation of the payment, and recommended no steps be taken against her.
Asked if Holomisa's expulsion from the party meant he would lose his seat in parliament, Zuma said: "His being in parliament is certainly affected by this decision."