The Murrumbidgee Local Health District's infectious diseases specialist Timothy Gilbey said the recent resurgence in cases in Melbourne's 12 "hotspot" postcodes "could happen anywhere".

Dr Gilbey was speaking with less than 12 hours to go before the NSW-Victoria border was closed to help slow the spread of COVID-19 from the latter.

Victoria has seen a skyrocketing number diagnoses of the virus in the past three weeks and today had 772 active cases.

Dr Gilbey said people on the northern side of the border needed to "remain vigilant" about social distancing and hygiene measures.

"Of course there's going to be a closure of the border ... regardless, we do have transmission in NSW," Dr Gilbey said.

"It's important not to be too fixated on one particular area although at the moment certainly areas of Melbourne and Victoria seem to be the main hotspots.

"The same thing could happen ... [wherever] people become lax and vigilance wanes.

Dr Gilbey said he was concerned about people having fled the resurgence of coronavirus cases in Victoria for NSW before the border closed.

He warned people against "trying to cheat what seems to be the rules".

"We saw similar behaviours in Italy early on in their outbreak and that led to kind of disastrous consequences," Dr Gilbey said.

"This pattern of fluctuating cases will continue for the duration of the pandemic and from my point of view it will continue until we have a widely available vaccine."

There were two new cases of coronavirus confirmed in Albury today.

Dr Gilbey said one of these was "the vector" to exposure in a Melbourne hotspot and there were now four people isolating as a result of that exposure and those cases.

"We have one case who had clear exposure to one of the areas in Melbourne that we know has elevated numbers of cases," he said.

Dr Gilbey said that person had relatively little minimal exposure to COVID-19 in Melbourne, yet had still caught the virus.

"The actual degree of contact in that area was relatively minimal and transient actually, just a train ride, taxi ride, even while trying to wear a mask and take precautions that way."

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