From 11.59pm on Friday, residents of Woollahra, Waverley, Randwick and the City of Sydney will need to stay home unless absolutely necessary, Premier Gladys Berejiklian said.

People can only leave home for work, education, exercise, to provide care or compassion, and to buy essential goods or services.

Anyone who has worked in the four areas in the past fortnight will also need to stay at home for the next week.

Ms Berejiklian said the stay-at-home order was proportionate to the risk.

"Please know that this is in order for us to ensure that this doesn't take a hold for weeks and weeks," she said.

Two community cases of COVID-19 were recorded in Queensland overnight, but both cases were in quarantine during their infectious period.

A total of seven cases of the Alpha COVID strain have been linked to the Brisbane cluster, with six people becoming infected after coming into contact with a flight attendant, who caught the virus in hotel quarantine.

But chief health officer Jeannette Young said she's more concerned about the evolving outbreak in NSW, especially with school holidays rapidly approaching.

"People should really reconsider their need to go anywhere in NSW," she said.

"If it's urgent, unavoidable, of course they should travel, but if it's not perhaps they should think about holidaying in Queensland."

There were also two local coronavirus cases recorded in Melbourne, both of which were announced on Thursday.

The first case is a man in his 60s who attended a party in Sydney which has since been deemed a super-spreading event.

That man is believed to have infected his boss at a Sandringham dry cleaners.

Genomic sequencing has revealed the men are linked to the NSW outbreak and have the highly infectious Delta strain of COVID-19.

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