Victoria reported another 134 cases on Wednesday, after the biggest daily increase since the start of hte pandemic saw 191 cases reported on Tuesday. There were 860 active cases in the state, with 41 people in hospital. There were 147 cases reported in Australia to 1.30pm on Wednesday, with 46 people in hospital.

The ACT reported three new cases of COVID-19, which were linked to the Victorian outbreak. They are the first cases in the territory for more than a month.

Eight new cases were recorded in NSW, including seven in hotel quarantine. A Victorian teenager holidaying in Merimbula on the state's South Coast also tested positive.

As more details emerged on how the border closure would be managed, we have answers on how it could affect you.

People seeking to cross the border into NSW from Victoria can apply for a permit from Service NSW.

No permit is required if you are entering NSW as an emergency services worker or law enforcement officer. People travelling to access medical or hospital services, avoiding injury or harm, or attending court can also still travel without a permit.

People travelling without a permit need to carry relevant documentation to demonstrate their eligibility to make the crossing to police stationed on the border.

Permits will be issued to returning NSW residents, politicians and diplomatic staff, seasonal workers, students and their parents or guardians, carers, and critical service workers.

People travelling through NSW to return to their home state or territory will also be granted permits,

Travellers seeking to cross the border for compassionate reasons need to apply to NSW Health for an exemption code before applying for a permit.

Once issued, the permits, which apply to road, air, sea and river crossings, are valid for 14 days and will indicate whether the permit holder needs to self-isolate for 14 days on arrival or get tested for COVID-19.

Travel permits will not be issued to people in Victoria who have been issued with stay-at-home directions as part of the state's return to stage three restrictions.

More than 50,000 vehicles crossed the border into NSW on Wednesday, NSW Police said.

Residents in towns on the NSW side of the border with Victoria will be eligible for a travel permit. Many people cross the border regularly for work and recreation in towns including Albury-Wodonga and Echuca-Moama, which straddle the Murray River.

NSW Premier Gladys Berejiklian on Wednesday said residents in border towns should not travel outside their communities.

Ms Berejiklian flagged a "border" north of Albury could be put in place to stop residents leaving the area, and warned other NSW residents from travelling to border towns.

"We are in a high-risk situation and I don't want to see the good work we've done in NSW undone," Ms Berejiklian said.

She said people living close to the border should be tested for coronavirus as soon as they experienced mild symptoms. Symptoms include fever, coughing, sore throat, shortness of breath, runny nose and headache.

"We have to protect the community," Ms Berejiklian said. "I ask anybody who feels that their freedom is limited, think about the consequences."

Deputy chief medical officer Dr Nick Coatsworth on Wednesday said in areas of increasing community transmission, like Melbourne, masks should be considered as an option for individuals.

In areas with no community transmission, widespread community mask use was not necessary, he said.

The Department of Health warns masks are not a substitute for other precautions to prevent the spread of the virus.

In situations where physical distancing is not possible - such as catching public transport - a mask may provide some protection, the department says. Masks need to cover your nose and mouth and fit snugly under the chin, over the bridge of your nose and against the sides of your face.

Medical experts continue to say people need to regularly wash their hands and maintain social distancing efforts.

The message is do not get complacent, despite low case numbers leading some people to pay less attention to restrictions and forget hygiene controls, distancing and limiting close social interactions.

People also need to stay 1.5 metres from others, even as some restrictions on activities and gatherings have been eased.

Everyone should continue to wash their hands often with soap and water, avoid touching their eyes, nose and mouth, and clean and disinfect regularly used surfaces.

Increasing fresh air flow by opening windows is also recommended.

Anyone with mild symptoms - such as a cough, sore throat, fever or runny nose - should stay at home and arrange to get a COVID-19 test.

After doing well to flatten the curve and limit the spread of COVID-19 infections, public concern has mounted that the Victorian outbreak could become a second wave.

The deputy chief medical officer, Professor Michael Kidd, on Monday told Channel Nine the Melbourne outbreak was not a second wave, a term often used to describe the Spanish flu pandemic in 1918-19.

"What happened then was the infection spread right across the country and resulted in even greater numbers of cases and greater numbers of fatalities than occurred in the first wave," Professor Kidd said.

"That is not what we are seeing at the moment in Melbourne. What we're seeing is an outbreak that is at the moment confined to the city of Melbourne, particularly in those lockdown areas, and we have a very rigorous response under way."