“Without voting machines, there will be no elections on December 23, 2018,” election commission head Corneille Nangaa told AFP, speaking on phone from New York.
The threat came a day after the United States, France, Britain and four other UN Security Council members called on Kabila to publicly declare that he will not run for election this year.
Washington separately asked Kinshasa to scrap plans to use electronic voting for the first time in elections this year, saying it risked undermining the credibility of the historic polls.
“These elections must be held by paper ballot so there is no question by the Congolese people about the result,” said US Ambassador to the UN Nikki Haley.
“The US has no appetite to support an electronic voting system,” she said, adding that e-ballots had never been tested in the country.
Kabila, 46, who has ruled for 17 years has not yet clearly stated whether he will step aside.
Congolese government spokesman Lambert Mende took a swipe at Washington, saying: “It’s not enough to say that electronic voting machines are bad, you have to provide a solution — notably how much money you are going to put on the table!”
According to government estimates, the elections will cost $432 million (349 million euros) with voting machines and $554 million if paper ballots are used.
Mende said it was up to the CENI, the national election commission, to take a decision, adding: “Nobody has the right to give orders to CENI.”
Opposition parties have said the electronic machines will lead to large-scale fraud and voter intimidation.
“We don’t want this machine,” said Vital Kamerhe, the leader of the third largest group in parliament.
“With these machines there will be no polling booths. When the voters choose their candidates on this machine, everything will happen under pressure from soldiers, the police and the secret service.”