The World Health Organization has said that people in Ireland should get into the habit of wearing face coverings, even if it's not mandatory to do so.

The WHO's Special Envoy on Covid-19, Dr David Nabarro, said while it is up to national governments to decide the policy on face coverings he wanted to encourage people to "take the advice super seriously and get into the habit of doing it".

Speaking to RTÉ's Saturday with Cormac Ó hEadhra, he said there was increasing evidence that the wearing of fabric face coverings can be useful in preventing the spread of Covid-19.

The WHO is recommending people to wear them. 

He said the organisation is also recommending that those over 60 and with underlying health conditions wear medical grade masks where they are indoors with others in a contained space that has limited ventilation. 

All other people should be wearing a fabric mask made up of at least three layers - Dr Nabarro said a single layer of fabric does not offer much protection

Asked about Ireland's decision to accelerate the roadmap for reopening, Dr Nabarro said he has always been a fan of the way Ireland has approached Covid-19 and he was going to continue to be positive.

But he said the only way of getting ahead of the virus was by everyone taking responsibility and that people need to remember that it's a dangerous virus.

WHO recently changed its advice on face masks amid the coronavirus pandemic, saying they should be worn in places where the virus is widespread and physical distancing is difficult.

The use of masks has been a hot topic ever since the pandemic first emerged in China in December.

"In light of evolving evidence, WHO advises that governments should encourage the general public to wear masks where there is widespread transmission and physical distancing is difficult," said WHO chief Tedros Adhanom Ghebreyesus.

Dr David Nabarro the WHO special envoy for Covid-19

In areas with community-level virus transmission, "we advise that people aged 60 years or over, or those with underlying conditions, should wear a medical mask in situations where physical distancing is not possible", he added.

But the UN health agency stressed that face masks alone "will not protect you from Covid-19" - and people suffering with the virus should not be out in public if they can avoid it.

The WHO maintained its recommendation that people who are sick with Covid-19 symptoms should stay at home and if it is absolutely necessary for them or their contacts to leave home, they should wear a medical mask.

As before, those caring for an infected person at home should wear a medical mask when in the same room; and health workers should wear medical masks plus protective equipment when dealing with suspected or confirmed Covid-19 patients.

Mr Tedros stressed that masks were only one part of an effective strategy to suppress the virus -- and should not lure people into a false sense of security.

He said they were not a replacement for physical distancing and hand hygiene.

"Find, isolate, test and care for every case, and to trace and quarantine every contact. That is what we know works. That is every country's best defence against Covid-19."

Coronavirus has infected at least 6.7 million people and killed more than 390,000 since the outbreak first emerged in China last December, according to a tally from official sources compiled by AFP.

All you need to know about wearing face masks in public