The Ebola outbreak raging in the Democratic Republic of the Congo (DRC) is growing "exponentially" with more than 2,500 deaths now recorded, with half in the last 20 days, the United Nations' senior Ebola coordinator said on Friday.

The Ebola outbreak is already the biggest in the country's history and is spreading faster than any outbreak on record.

According to the latest figures, the virus eruption is "growing exponentially," Julien Harneis told reporters in Geneva, speaking from Bunia, at the epicentre of the outbreak.

He said that in the last three months, "more than 2,500 people" had died, "and half of those in the last 20 days."

"The epidemic is spreading widely. It's now covering an area that is bigger than France....It is growing faster and wider than the Ebola response."