Sierra Leone said Friday that between 80 and 100 new cases of Ebola are being reported every day and the country now hardest-hit by the deadly virus desperately needs over 1,000 beds to treat victims.

Sierra Leone's Finance Minister Kaifalah Marah painted a grim picture to the U.N. Economic and Social Council Friday of the challenges facing his West African nation which failed to meet a World Health Organization interim goal of isolating 70 per cent of Ebola patients and safely burying 70 per cent of victims by Dec. 1.

The two other hard-hit countries, Liberia and Guinea, did meet the deadline, and the U.N.'s Ebola chief Dr. David Nabarro said the number of new cases in Liberia has dropped from 60 per day in September to 10 per day now.

But Nabarro and WHO Director-General Dr. Margaret Chan stressed that Ebola that a much greater effort is needed to reach the elusive goal of zero new cases.

"The Ebola outbreak is the largest, longest, most severe and most complex Ebola epidemic in the nearly 40-year history of this disease," Chan said. "What began as a health crisis has become a crisis with humanitarian, social, economic and security implications."

She said by videoconference from Geneva that "the fear for Ebola is moving faster than the virus."

Marah said as of Thursday there were 6,201 confirmed Ebola cases in Sierra Leone and 1,900 deaths, and the virus is now concentrated in some northern districts and the western area including the capital, Freetown.

Sierra Leone has four functioning treatment centres but it needs 12, and while the number of beds for Ebola sufferers has increased from 212 to 406 it needs 1,500 -- which means 1,094 additional beds, he said.

Marah said Sierra Leone also needs 6,000 people to scale-up the tracing of contacts of Ebola victims.

Chan said clinical trials for an Ebola vaccine "look promising," and experimental therapies including some potential cures are also undergoing clinical trials.

"Most experts are convinced that this will not be Africa's last Ebola outbreak," Chan said. "At least 22 African countries ... have the ecological conditions, the wildlife species, and the hunting practices that favour a return of Ebola at some time in the future."