New variant of COVID-19 discovered in Melbourne - with no link to current cases

A new COVID-19 variant has been discovered in Melbourne - not linked to any of the other outbreaks across the country.

On Friday morning Victoria's chief health officer Brett Sutton said the new variant was discovered overnight. 

"[It is] the Delta variant. It is infamous in India and in the United Kingdom. It is a variant of significant concern," Sutton is quoted as saying by 7 News.

"It has not been linked to any sequence cases across Australia from hotel quarantine or anywhere else that it is not linked in Victoria or any other jurisdiction."

He went on to say there is anecdotal evidence this variant has greater severity and transmissibility in children. 

The family who contracted the variant had travelled to Jervis Bay and Sutton says it's "within the bounds of possibility" they picked it up in New South Wales.

"We are examining who is the likely index case in this family, and therefore trying to trace back, where this variant has been picked up."

There are now 67 active cases in Victoria.

The state's lockdown was extended a further week on Wednesday, with Sutton saying it was to "get completely on top" of the virus.

"The lockdown is to make sure that we see cases who are already quarantining, like one of the new cases from overnight," he explained.

"I would love to see cases driven down to zero by virtue of that, but if the number of exposure sites stabilise and we are really not seeing new or concerning exposure sites, that gives us all great confidence that we can ease up."