Congolese opposition presidential candidate Martin Fayulu and other opposition candidates address a news conference in Kinshasa, Congo. Picture: Jerome Delay/AP

Kinshasa - Congo has delayed December elections in several areas until March 2019 due to an ongoing Ebola epidemic and violence, the electoral commission said Wednesday.

The country-wide vote - due to take place in most of Congo on Sunday - has already been delayed by a week.

The commission announced that Beni and Butembo towns in eastern Congo and Yumbi in the west will now hold their polls months later.

The delay is due to "the persistence of the Ebola epidemic in Beni, North Kivu province ... as well as the terrorist threat" there and several deadly attacks in Yumbi, Mai-Ndombe province, the body said.

The election - initially set for December 23 and then pushed back to December 30 - was delayed for two years by President Joseph Kabila, in power for 18 years, causing mass protests.

The opposition, which is divided and fielding two main candidates, had already expressed concern that the vote will not be free or fair.

One opposition leader, Felix Tshisekedi, said last week that if the polls were again delayed further than December 30, his supporters would take to the streets.

Tshisekedi and fellow opposition leader Martin Fayulu are facing off against ruling party candidate and Kabila protege Emmanuel Ramazani Shadary.

On Wednesday, Fayulu tweeted his concern about Ebola being used as an excuse to stop elections.

"I caution (the electoral commission) against any attempt to cancel the elections in #Beni city, Beni territory and #Butembo. The pretext of Ebola is fallacious ... This is yet another strategy to divert the truth from the polls," he said.

Beni is an area with strong opposition support.

The Ministry of Health has for months been saying there were measures in place in the east to allow people to cast their ballots despite Ebola and that the outbreak would not affect the vote.

Congo, a mineral-rich country with an impoverished population, is already battling crises on multiple fronts: a hunger crisis in the central Kasai region, the deadly Ebola outbreak in the east, and numerous militia groups.

Last week, the United Nations Security Council called on all parties in Congo to "ensure transparent, peaceful and credible elections and to preserve peace and stability."