Describing the Ebola outbreak as a threat to world peace, the UN Security Council is set to adopt a resolution urging countries to provide field hospitals and other urgent aid to West Africa.
A draft of the resolution obtained by AFP also calls on nations to lift travel and border restrictions, and asks airlines and shipping companies to maintain their links with affected countries.
The council is expected to approve the resolution at an emergency session on Thursday, marking only the third time that it will be voting on measures to address a public health crisis.
The top world body adopted resolutions to combat AIDS in 2000 and 2011.
"This has gone beyond health issues," UN Secretary General Ban Ki-moon said of the epidemic that has killed more than 2,400 people in Guinea, Liberia, Nigeria and Sierra Leone.
"It has gone to areas affecting social and economic situations. It may even affect political stability if not properly contained and treated."
UN: Nearly $1b needed now to stop Ebola
The number of Ebola cases in West Africa could start doubling every three weeks and it could cost nearly $1 billion to contain the crisis, the World Health Organisation said.
Even as US President Barack Obama was expected to announce the deployment of 3,000 American forces to help provide aid in the region, Doctors Without Borders said the global response to Ebola has been far short of what is needed.
"The response to Ebola continues to fall dangerously behind," Dr Joanne Liu, president of the medical charity, told a UN special briefing on Ebola in Geneva. "The window of opportunity to contain this outbreak is closing. We need more countries to stand up, we need greater deployment, and we need it now."
In a report released Tuesday, WHO said some US$987.8 million is needed for everything from paying health workers and buying supplies to tracing people who have been exposed to the virus, which is spread by contact with bodily fluids such as blood, urine or diarrhoea. Some US$23.8 million alone is needed to pay burial teams and buy body bags, since the bodies of Ebola victims are highly infectious and workers must wear protection suits.
Nearly 5,000 people have been sickened by Ebola in Liberia, Sierra Leone, Guinea, Nigeria and Senegal since it was first recognised in March. WHO says it anticipates that figure could rise to more than 20,000. At least 2,400 people have died, with Liberia bearing the brunt of the fatalities.
Recent weeks have seen a flurry of promises of aid.
In addition to the US forces, the UN health agency said China has promised to send a 59-person mobile laboratory team to Sierra Leone that includes lab experts, epidemiologists, doctors and nurses. Britain is also planning to build and operate an Ebola clinic in Sierra Leone, and Cuba has promised to send the country more than 160 health workers.
"The question is translating these commitments into quick action on the ground," said Dr Unni Krishnan, head of disaster preparedness and response for the aid group Plan International.
Still, hospitals and clinics in West Africa are now turning the sick away because they don't have enough space to treat everyone - a sure-fire way to increase the spread of the disease, which in this outbreak is killing about half of those it infects.
The United States, in particular, drew criticism last week when it promised to set up a 25-bed field hospital in Liberia to serve health care workers, both local and foreign, who become infected. Many thought the contribution was paltry, given that experts were saying Liberia needed at least 500 more treatment beds.
In addition to the troop deployment, Obama is expected to promise on Tuesday to build more than a dozen treatment centres in the afflicted region.
Tracing the rise of Ebola in West Africa
Since the Ebola outbreak first emerged in West Africa, The Associated Press has been reporting on it. A timeline compiled from AP dispatches since March shows the dreaded disease being identified in a remote part of Guinea and then spreading to another country and then two more nations with authorities being alternately alarmed or confident.
The outbreak is now out of control and the US is planning to send in military personnel and equipment as part of the international effort to try and bring it under control.
March 23: Guinean officials say tests confirm that it is the Ebola virus that has killed 59 people. Health officials and Doctors Without Borders establish treatment centres.
March 28: Health officials confirm Ebola has spread from a remote forested corner of southern Guinea to the country's seaside capital.
March 30: Ebola crosses the border into Liberia, where the health minister says two patients have tested positive for the deadly virus.
April 5: A crowd angry about the Ebola outbreak that is believed to have killed 86 people across Guinea attacks a centre in the country where patients are being held in isolation, prompting an international aid group to temporarily evacuate its team.
May 9: The World Health Organisation says health workers have made dramatic progress in controlling the Ebola outbreak in West Africa in recent weeks, blaming it for at least 168 people in Guinea and Liberia. There are signs that the spread is slowing but it is not over yet, says a WHO official.
May 30: The first two Ebola deaths are reported in Sierra Leone.
June 12: The Sierra Leone government announces a state of emergency in the Kailahun district because of the Ebola outbreak which has claimed 17 lives in this West African nation, banning public gatherings and closing schools.
June 17: Ebola is now also in Liberia's capital, with a health official saying seven people have died there.
June 18: This appears to be the largest Ebola outbreak ever recorded, says an American doctor who has responded to the outbreak. The World Health Organisation attributes more than 330 deaths to Ebola.
June 20: The Ebola outbreak ravaging West Africa is "totally out of control," according to a senior official for Doctors Without Borders, who says the medical group is stretched to the limit in responding.
July 23: The doctor in charge of battling Sierra Leone's current Ebola outbreak has himself become ill with the deadly disease, the country's health minister confirms. He later dies.
July 25: The outbreak spreads to Nigeria, the continent's most populous nation, after a Liberian man with Ebola takes a flight to Lagos and dies there.
July 27: One of Liberia's most high-profile doctors has died of Ebola, a government official says.
July 31: The death toll attributed to Ebola has risen to more than 700 people in West Africa and the disease is moving faster than efforts to control it, the head of the World Health Organisation warns as presidents from the affected countries meet in Guinea's capital.
Aug. 17: Liberian officials fear Ebola could soon spread through the capital's largest slum after residents raided a quarantine centre for suspected patients and took items including bloody sheets and mattresses.
Aug. 20: The World Health Organisation says the death toll from the Ebola outbreak in West Africa is believed to be at least 1,350 people. The UN health agency also warned in its announcement that "countries are beginning to experience supply shortages, including fuel, food, and basic supplies."
Aug. 29: Senegalese officials announce that a university student infected with Ebola evaded health surveillance for weeks as he slipped into Senegal, carrying the deadly virus to a fifth West African nation. With mass quarantines, border closures and flight bans failing to contain the outbreak, public health officials intensified efforts to identify and contain the sick.
Sept. 13: Sierra Leone loses a fourth doctor to Ebola, a huge setback to the impoverished country that is battling the virulent disease amid a shortage of health care workers.
Sept. 16: The Obama administration ramps up its response to West Africa's Ebola crisis, preparing to assign 3,000 US military personnel to the afflicted region to supply medical and logistical support to overwhelmed local health care systems and to boost the number of beds needed to isolate and treat victims of the epidemic.
Next article: Explainer: What is the Ebola virus?