The World Health Organisation has said that the Ebola outbreak in West Africa no longer constitutes an international emergency, voicing confidence that remaining isolated cases in the affected countries can be contained.

"The Ebola outbreak in West Africa no longer constitutes a public health emergency of international concern," WHO's chief Margaret Chan told journalists, officially ending the emergency first declared in August 2014.

The deadliest-ever outbreak of the tropical disease emerged in December 2013 and killed more than 11,300 people, mostly in Guinea, Liberia and Sierra Leone.

Ms Chan stressed that all three countries remain vulnerable to flare-ups, including an ongoing cluster of cases of Guinea, which has left five people dead. 

"The risk of international spread is now low, and... countries currently have the capacity to respond rapidly to new virus emergences," the head of the United Nations public health agency added.

She also warned against complacency towards the virus, which remains in "the ecosystem" in West Africa and said that vigilance was crucial, including quick reactions to new cases.

"Particularly important will be to ensure that communities can rapidly and fully engage in any future response, cases are quickly isolated and managed," Ms Chan said.