National Unity Democratic Organisation (Nudo) members have demanded that the party's leadership hold the congress.
They claim that postponing it is an attempt to illegitimately capture the party.
Nudo members yesterday handed over a petition to the chiefs within the party and gave them two days to respond.
The party has postponed their elective congress more than once due to fights over factionalism and a lack of finances.
Nudo president Esther Muinjangue in July had to call off the congress because of chaos and anarchy at the venue.
Nudo member Tjizapouzeu Uahupirapi, who read the petition yesterday afternoon, denied there was any violence.
"The national council never passed a resolution to postpone the 2024 congress, and there were no incidents of violence or disorder at Ramatex, as any such behaviour would have been reported to the police.
"The unlawful postponement of the congress suggests an attempt to illegitimately capture the party and extend an expired mandate. We urge you, esteemed traditional chiefs and Kainamatui, to address this matter urgently to prevent further damage to Nudo," he said.
Uahupirapi said the delegates were prepared for the congress and were dismayed by the sudden postponement, adding that Muinjangue's team interpreted Nudo's constitution wrong.
"The former leadership must cease making media statements suggesting that hosting the congress is constitutionally impossible. Their interpretation of the constitution is incorrect and indicative of their lack of understanding of the document," he said.
Sign up for free AllAfrica Newsletters
Get the latest in African news delivered straight to your inbox
He also wants the appointment of an interim committee.
"An interim committee must be appointed to lead the party and organise the 2024 Nudo congress, including compiling the master list of congress delegates," the petition reads.
Nudo secretary general Joseph Kauandenge has disputed allegations that the party's leadership is illegitimate.
"As far as the leadership is concerned, we will have our national executive committee meeting by the end of the month to pave the way forward regarding the party's preparations for the upcoming elections, and other issues," he says.
Kauandenge says he cannot comment on the content of a letter that was not directed to the leadership.
"This leadership under president Muinjangue is the legitimate leadership of the party until the holding of another congress. The mere fact that the congress did not take place does not say that this leadership ceased to exist," he says.
Muinjangue yesterday confirmed seeing the letter and told The Namibian that she cannot give an answer for allegations in a letter that was not directed to her.
