Chair in Epidemiology Professor Catherine Bennett, from Deakin's Institute for Health Transformation, said a recent paper had found there was sufficient evidence to show that wearing a mask provided additional protection as long as other precautions were in place.

She said the paper looked at "natural experiments where some cities and countries have used masks and some haven't."

"This is going to be more so where you have a higher prevalence of people positive in the community... and the masks might make a difference if you are close by and obviously it's going to be more useful in areas... where even if you can maintain 1.5 metre distancing, usually it's just those moments when you don't and you're caught at a checkout or whatever," she said.

"That's when it can make a difference. So there is sufficient evidence to say that outweighs inconvenience.

"It just gives us that extra layer and hopefully that will stop the spread within regional centres, even if there has been one or two cases nearby."

Professor Bennett said a concern with advising people to wear masks was that they would ignore other health advice including to stay home if unwell.

"There's another concern that sort of balances the value in wearing masks and that is that people don't think that they can go out if they've got symptoms," she said.

She said people shouldn't let their guard down and think they can go out it with a mask if they have symptoms.

"The benefit of masks is really just that risk reduction and assuming everything else is in place," she said.

"The other precautions that we've already had in place for a long time. Now that's the key, this is added onto that. It can't replace it.

"So if you don't distance whether you're wearing a mask or not, your risk of infection goes up. In Melbourne we're seeing, to date, a capping of the number of daily cases, what we want is for that to start to drop and the idea of wearing masks now is that it might speed that process up just by giving that extra barrier of transmission into the community."

Premier Daniel Andrews has encouraged regional Victorians to wear a mask if they were out of their house and couldn't maintain 1.5 metres from another person. "When we say mask it might be one you've purchased, it might be one you've made, it might even be a scarf," he said. "Numbers are low in regional Victoria and we want to try and do everything we can to keep them low and wearing masks is just a logical next step."

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