"We are advising governments to encourage that the general public wear a mask", Dr Van Kerkhove said.
People over 60 or with health issues should wear a medical-grade mask when they are out and can not socially distance, according to new guidance from the World Health Organization, while all others should wear a three-layer fabric mask.
In the United Kingdom, the government announced on Friday that hospital visitors and out-patients would be required to wear face coverings, and that hospital staff would have to wear medical masks, even if they were not in a clinical setting.
World Health Organization director-general Tedros Adhanom Ghebreyesus said at a thrice-weekly video press conference that he wanted to talk about who should wear masks, what materials they should be made of and when they should be worn. This includes public transport, shops or in other confined or crowded environments.
We've already reported that from 15 June, people in England will be required to wear face coverings on public transport.
The guidance comes after months of the World Health Organization expressing uncertainty around the level of protection of face masks and their ability to prevent the spread of viruses such as COVID-19.
The organisation had always advised that medical face masks should be worn by people who are sick and those caring for them.
The ministry's latest advice states that "there is no convincing evidence one way or other to require the use of non-medical face masks for healthy people in the community to protect them from COVID-19". It is still unknown whether the wearers of masks are protected, say its experts, but the new design it advocates does give protection to other people if properly used.
'Masks are only of benefit as part of a comprehensive approach in the fight against COVID-19.
"Masks can also create a false sense of security, leading people to neglect measures such as hand hygiene and physical distancing", he said.
'The cornerstone of the response in every country must be to find, isolate, test and care for every case, and to trace and quarantine every contact.
Based on new academic research, Tedros said the World Health Organization advised people to wear masks consisting of at least three layers of different materials, as outlined in the guidelines, if wearing fabric variants. It added that this is what they know works and it is every country's best defense against COVID-19.