It's an escalation of advice from recommendation to obligation from the Victorian state government, with mask sales expected to rise across the country in anticipation of potentially similar rules elsewhere.

So for those taking precautions, how should you go about it?

Ideally, you'll be able to purchase a cloth mask.

Surgical masks are easier to purchase, available at chemists and some smaller supermarkets, but are strictly one-use only and cannot be washed.

Cloth masks are reusable and are available from a number of retailers in a variety of styles, though they may be in shorter supply due to demand following the announcement of new rules in Victoria. An aggregate list of cloth mask retailers in Australia is available at Finder.com.au.

The P2 or N95 masks you may have leftover from the summer's smoke are not recommended for community use by the Victorian DHHS.

A 50-pack box of disposable surgical masks will cost you approximately $50 from a chemist retailer, while the price of cloth masks can vary depending on the style.

Australian-made cloth face masks from the Australian Facemask Company retail online for $34.90, while the prices of those sold by fashion brands ASOS, Dangerfield and Gorman range from $12-$36 for a three-pack.

The Victorian DHHS rules dictate only that you need to wear a "face covering", meaning you can legally wear a bandana, scarf or another kind of fabric which may prevent some small virus-carrying droplets from getting through to your nose and mouth.

They stress however that they are not as effective as a fitted face mask, which should have "three layers of materials, including a water-resistant outer layer". Experts agree, saying the efficacy of homemade or cheaper masks varies.

"The filtration of cloth is quite variable and single layers of scarf, sweatshirt and t-shirt may be in the 10 to 40 per cent range," Dr Catherine Clase, professor of medicine at McMaster University, said.

"But multiple layers increase efficiency, and modern studies have confirmed that some combinations of cloth, for example cotton-flannel, block more than 90 per cent of particles."

Regardless of what you wear, you must change and wash the mask regularly. The Victorian DHHS says a cloth mask should be washed every day after use, but asks people to apply commonsense; if the mask appears dirty or wet, wash it.

Washing the mask with other clothes is fine, and if you'd prefer to do it before you put on a load in the machine, you can also wash the mask with hand soap and the warmest water acceptable for that mask. The mask must be dry before reusing it, otherwise it will not be effective.

Since mask-wearing has been far more common in the US during the crisis to date, there are a lot of online tutorials which can show you how to make your own mask.

One of the most accessible is a TikTok video demonstrating how to make a mask with a single sock, from a dancer in Amsterdam. She cuts half the foot section off and slices it open down the middle. She then folds it open with the heel area in the centre and cuts two slits into either side. The slits are then used to clip it around the ears.

The Victorian government has also issued an official instructional video on how to make a mask with three squares of 25cm x 25cm fabric. In the video, a demonstrator folds over one centimeter for the top and bottom hems, and one-and-a-half centimeters for the side hems, stitching both. They then run elastic through the hems on each side and knot the ends.

Instructions on mask-wearing varies for cloth and surgical masks. The DHHS recommends the following for cloth masks, in line with similar instruction from The World Health Organisation:

To remove the mask, advice says to again wash your hands for at least 20 seconds with soap and water, or hand sanitiser that is at least 60 per cent alcohol. Then, remove the ties or loops from the back of your head delicately, fold the mask and place it a clean bag for laundering. Again, wash your hands for at least 20 seconds with soap and water, or hand sanitiser that is at least 60 per cent alcohol.

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For surgical masks, the process is much the same.

This time, place the coloured side of the mask outward, ensuring the metallic mouldable strip sits at the top on the bridge of your nose.

Use this to fit the mask to your face, pinching and pressing down on it with your fingers. At the end of use, dispose of it responsibly and wash your hands.

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