The group accused the WHO's Global Alert and Outbreak Response Network of ignoring desperate pleas for help from Liberia when it met in June.
International medical group, Doctors Without Borders has slammed the international community for what it termed as a its slow response to the Ebola epidemic.
In a report, the group said "months were wasted and lives were lost" because the UN's World Health Organization (WHO), which is charged with leading on global health emergencies and "possesses the know-how to bring Ebola under control", failed to respond quickly or adequately.
It further accused the WHO's Global Alert and Outbreak Response Network of ignoring desperate pleas for help from Liberia when it met in June.
Marie-Christine Ferir, emergency coordinator for the aid agency said:
"I remember emphasising that we had the chance to halt the epidemic in Liberia if help was sent now, It was early in the outbreak and there was still time. The call for help was heard but no action was taken."
However, WHO did not set up a regional hub for coordinating the response until July, by which time a second wave of the epidemic had struck.
According to Ferir, MSF had only 40 staff with experience of Ebola when the outbreak began.
"We couldn't be everywhere at once, nor should it be our role to single-handedly respond," said Brice de le Vingne, MSF director of operations.
According to Al Jazeera, the group the said it was only when a US doctor and Spanish nurse were diagnosed with Ebola that the world woke up to the threat.
The aid agency further blamed the governments of Guinea and Sierra Leone for refusing to admit the scale of the epidemic, saying they put "needless obstacles" in the path of MSF teams.
WHO, however did not immediately respond to a request for comment.