The price of disposable face masks is spiking online as Americans gird for a widening outbreak of the coronavirus. Consumer demand for the medical accessory appears to be surging even as government officials say healthy individuals do not need to wear the masks.

As of Wednesday afternoon, Amazon had largely sold out of different mask varieties. Keepa, which tracks the prices of items sold on Amazon, shows that a 10-pack of 3M N95 respirators that sold for $18.20 roughly a month ago now costs $99.99. And one Amazon seller is offering a 30-pack of 3M N95 respirators for $198.98. On eBay, a two-pack of 3M N95 face masks is available for $59.99. Other retailers typically sell a pair of masks for less than $6, but are currently out of stock.

One Amazon customer told CBS MoneyWatch they bought 100 3M N95 respirator masks this week for $10 each, spending a total of $1,000 — an indication of the growing consumer anxiety about the risks of contracting the coronavirus in the U.S.

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N95 masks are in demand because they filter out 95% of all airborne particles, according to the U.S. Centers for Disease Control and Prevention. Yet the agency has noted that only people with coronavirus symptoms should use protective masks as a measure to help contain the disease. They are also recommended for health workers and others caring for infected patients.

Prices are rising as mask supplies run short. Prestige Ameritech, the largest surgical mask manufacturer in the U.S., said this week that it's struggling to keep up with demand for its products, including face masks and respirators. And masks made by consumer products company 3M are also sold out online at retailer sites including CVS, Home Depot, Sam's Club, Target and Walmart.

A screen shot of its website shows that Prestige Ameritech, the largest manufacturer of face mask in the U.S., has none in stock. Prestige Ameritech

Amazon sellers set their own prices for goods sold through the ecommerce giant's online marketplace. Yet the company seeks to ensure "fair pricing" and this week has warned some sellers that they risk being suspended if they violate its pricing policies. That could include setting a price for a product or services that is "significantly higher than recent prices offered on or off Amazon" or charging excessive shipping and handling fees.

Amazon is cracking down on such instances of price-gouging and on Thursday told Reuters that in recent weeks, the company removed tens of thousands of deals from merchants it accused of charging customers unfair prices.

"We have absolutely enforced the policy," an Amazon spokesperson told CBS MoneyWatch. "We identify them and quickly take action," the spokesperson added.

Amazon told Reuters it has also taken down more than 1 million other products that falsely claim to protect consumers from the coronavirus.

A screenshot shows that one Amazon seller is offering a 30-pack of 3M N95 respirators for $198.98. Amazon.com

Ed Rosenberg, a third-party merchant on Amazon who also runs a support group for other sellers, said he's aware of five different mask sellers who have been removed from Amazon for setting their prices too high.

"This is a gray area because it is a medical item, but there's no national emergency in the United States," he said. "Yes, it looks bad that they are raising their prices. But I think Amazon is between a rock and a rock because on the one hand the optics aren't great if they are letting people raise prices, but on the other hand it's just supply and demand."

Some mask sellers have tried to charge up to five times more than their usual prices, said Rosenberg, who noted that manufacturers are also facing higher costs. "They aren't pulling masks out of the garage. Their costs have gone up, too, because either the masks are being made locally and are more expensive, or suppliers are charging the list price instead of offering discounts."

A total of 15 people in the U.S. have been diagnosed with the coronavirus, officially known as COVAD-19, but the CDC warned Tuesday that it expects many more cases to emerge.

Mask makers in China are also working overtime to keep up with demand — and some Chinese electronics factories have begun manufacturing masks.

Mike Bowen, executive vice president and partner of Prestige Ameritech, told CBS News that the company has seen a thousandfold increase in demand for its face masks and respirators since COVAD-19 emerged from China. All of the company's 17 mask and shield products are sold out on its website.

"Due to high demand from our hospital customers, we are no longer able to add more products to this store," the website reads. Its products aren't available for sale on Amazon either, the company notes.

Gwyneth Paltrow on Wednesday shared a photo of herself on Instagram wearing a reusable Airinum face mask that retails for $99. They are sold out on the health accessory company's website.

U.S. Secretary of Health and Human Services Alex Azar said the government has a stockpile of 30 million masks of different varieties, although he warned that N95 masks must be fitted and tested in order to be effective. The government is looking into producing roughly 300 million more N95 masks, but it's unclear when that will happen.

Mask prices are also skyrocketing in Italy, where more than 260 cases of coronavirus have been reported. Authorities there are investigating soaring prices for hygienic masks and hand sanitizer.

"We have decided to open an investigation after media reports of the insane prices fetched up by these products (masks and gels) on online sales websites in the last two days," Milan's deputy chief prosecutor told Reuters.