There has been a "dramatic increase" in face masks being bought as some think they may help halt the coronavirus spreading, a supplier has said.
The outbreak has killed 170 in China and infections have spread to at least 15 other countries. People have been tested for the virus in the UK.
One medical supplies firm has sold out of its entire 500 face-mask stock.
But Public Health Wales said there was "insufficient evidence" to suggest there was any benefit from wearing one.
The agency added people should only do so if directed to by a doctor.
Wynne Lloyd-Williams, of Cymru Healthcare, said they had seen a spike in demand for face masks.
Mr Lloyd-Williams, managing director of the Merthyr-based medical supplies firm, said it had sold its entire stock of 500 masks to a Chinese buyer from Leicestershire.
"We've seen a dramatic increase in demand," he said.
"This is unusual. They are not a significant product, but people now are thinking 'should we purchase them?'"
Do the masks help stop viruses spreading?
Surgical masks were first introduced into hospitals in the late 18th Century but they did not make the transition into public use until the Spanish flu outbreak in 1919.
Using them to prevent infection is popular in many countries around the world but virologists are sceptical about their effectiveness against airborne viruses, although there is some evidence to suggest they can help prevent hand-to-mouth transmissions.
One man with cystic fibrosis said he was concerned about the availability of respirator masks due to the outbreak.
Byron Wright had a lung transplant and has a suppressed immune system so uses a mask to protect against viruses.
The 37-year-old's wife Glesni said viruses increase the risk of his body rejecting the new organ.
She said it was harder and more expensive to buy the masks online since the outbreak in China.
Mrs Wright, 36, who is her husband's full time carer, has been online to order respirator masks, but she was refunded her money as the company could not fulfil the order.
Following more searching online, she was able to buy some masks, but she said prices had increased due to demand.
A pharmacy in Cardiff told BBC Wales that, while it does not stock face masks, it had received up to 30 queries in recent days.
The coronavirus death has prompted people in the affected areas to wear the masks when in public in the hope it helps stop the spread of the virus.
But the increase in demand has caused problems for the Wrights, who live in Manod, Blaenau Ffestiniog.
"Since the coronavirus started we are taking more precautions and wanted to make sure we had enough masks," said Mrs Wright.
"I started to look on other websites and saw that many are out of stock and the ones available had significantly increased in price.
"You could get 10 masks for £10 but now they are around £6 to £10 each. This is a worrying time for people like us who depend on these types of masks.
"Some people don't care if they get a cold or a virus, they go to work as usual, but it can change our lives forever."
But a Public Health Wales (PHW) spokesman said: "There is insufficient evidence to suggest that there is any benefit to members of the general public from wearing a face mask.
"The risk to the general public from the N-CoV infection remains low.
"Public Health Wales would not encourage people to buy or start wearing face masks unless they have been directed to do so by a clinician."
A Boots spokesman added: "The best way to help prevent catching a virus is by making sure you regularly wash your hands with soap, and avoid touching your eyes, nose or mouth to prevent transmission from surfaces, especially after blowing your nose, sneezing and coughing.
"Antiviral hand foams and gel can also be useful when you are out and about."
The Foreign Office said it would fly 200 British citizens to the UK from Wuhan early on Friday before they are put in quarantine for two weeks on their arrival.
Lecturer Yvonne Griffiths from Cardiff as been stuck in a hotel in Wuhan after the flight, which was originally set to depart of Thursday, was delayed because of a lack of clearance.
She said: "There's uncertainty where we will be staying for two weeks [during quarantine] and the conditions to expect when we get back."
PHW said some residents in Wales had been offered screening for the virus as they "meet the current testing criteria", but they would not say how many as numbers were "so low".
The UK's Department of Health said on Wednesday that 130 people had been given the all-clear for the new coronavirus which can cause severe acute respiratory infection.