About 400 scientists were taking part in the two-day international meeting in Geneva which will review how the virus is transmitted and possible vaccines against it.
"With 99% of cases in China, this remains very much an emergency for that country, but one that holds a very grave threat for the rest of the world," WHO head Tedros Adhanom Ghebreyesus said at the start of the meeting.
"What matters most is stopping the outbreak and saving lives. With your support, that's what we can do."
The virus, first identified in the city of Wuhan in central China on December 31, has killed more than 1,000 people, infected over 42,000 and reached some 25 countries.
WHO has declared it a global health emergency.
Participants at the scientific conference will also discuss the source of the virus, which is thought to have originated in bats and reached humans via another "intermediary" species such as snakes or pangolins.
WHO sent an advance team to China this week for an international mission to examine the epidemic.
It was unclear, however, whether the team would be able to visit Wuhan, which has been under lockdown after the outbreak was registered in a food and
'Roadmap for research'
There is no specific treatment or vaccine against the virus and WHO has repeatedly urged countries to share data in order to further research into the disease.
"That is especially true in relation to sharing of samples and sequences. To defeat this outbreak, we need open and equitable sharing, according to the principles of fairness and equity," Tedros told the scientific conference.
He said he hoped the scientists could agree a roadmap "around which researchers and donors will align."
Asked whether scientists from Taiwan would take part, WHO officials said that they would do so but only online – along with colleagues from other parts of China.
While the WHO does not deal with Taiwan directly and only recognizes Beijing, Taiwan was often allowed to attend annual assemblies and sideline meetings as an observer.
But in recent years it has been frozen out as Beijing takes an increasingly combative stance towards Taiwan, which it considers its own territory.
Animal testing of vaccine
The WHO said it was applying a so-called R&D Blueprint, which allows the rapid rollout of research and development activities during epidemics.
Several teams of experts in Australia, Britain, China, France, Germany and the United States are racing to develop a vaccine – a process that normally takes years.
This week, a team of scientists at Imperial College London said they believed they had become the first to start animal testing of a possible vaccine in mice.
Efforts to come up with a vaccine are being led by the Coalition for Epidemic Preparedness Innovations (CEPI), a body established in 2017 to finance costly biotechnology research in the wake of an Ebola outbreak in West Africa that killed more than 11,000 people.
Ultimately, however, scientists may end up in the same situation they were during the 2002-2003 outbreak of Severe Acute Respiratory Syndrome (SARS) – it died out before a vaccine could be fully developed.
A close cousin of the new coronavirus, SARS spread around the world and killed nearly 800. – Rappler.com