Premier Gladys Berejiklian predicted the number of new COVID-19 infections would grow as the hundreds of people currently in isolation return positive tests.

"We expect household contacts to develop the virus," the premier told reporters after a crisis meeting to review the swelling figures.

"Our aim is to make sure that we get on top of any potential spread and that we also get on top of any chains of transmission that our testing hasn't picked up."

NSW recorded 22 new local COVID-19 cases on Friday.

Eleven cases were detected in the 24 hours to 8pm on Thursday night, six of which were already reported. There were 17 further infections after 8pm which will be recorded in Saturday's tally.

There are now 65 cases linked to the Bondi cluster that erupted in the city's east last week.

The premier said the stay-at-home orders will come into force from midnight. People who live or work in Woollahra, Waverley, Randwick and the City of Sydney council areas will not be able to leave home for a week except for essential purposes.

These include work or education, shopping, providing care or outside exercise.

Yet Australian Medical Association president Omar Khorshid said a targeted lockdown was "not quite enough" to get a hold on the circulating Delta variant of the virus.

"What we really need are clear rules for all Sydneysiders that say 'stay at home' so we can get ahead of this virus and stop further transmission," Dr Khorshid said.

"An alternative and what the AMA believes will be the right move is a lockdown of the Sydney basin."

The government had previously held off declaring a lockdown, instead preferring to restrict the movements of residents, increase mask wearing and limit social and other gatherings.

Ms Berejiklian announced those restrictions - still in place for other areas of Greater Sydney as well as the Central Coast, Blue Mountains, Wollongong and Shellharbour - would be extended until midnight on Friday next week.

Those who live or work in the Inner West, Canada Bay or Bayside council areas, meanwhile, are still barred from leaving metropolitan Sydney.

NSW Chief Health Officer Kerry Chant said the stay-at-home orders would act as a "circuit breaker" to give contact tracers time to get on top of exposure sites.

Dr Chant said she was more concerned about people who had been infectious in the community before isolating, such as clients of Joh Bailey hairdressers in Double Bay.

"We have at least three staff members who were working whilst infectious and with two confirmed cases amongst clients so far I expect more cases to be detected over the coming days," she said.

Dr Chant said 17 of the guests at a "super-spreader" birthday party in Hoxton Park earlier this week have now tested COVID-positive.

NSW Health added several exposure sites including two cafes in Potts Point, two cafes in Alexandria and a health club in Bondi Junction to its list of venues of concern on Thursday evening and Friday.

The National Retail Association said the seven-day lockdown would "inflict carnage" on CBD retailers and cost as much as $750 million in lost sales, while the Shop, Distributive and Allied Employees' Association called for shoppers to show respect to frontline staff.

Meanwhile, Deputy Premier John Barilaro has tested negative to COVID-19 after a virus scare in the state's parliament but must remain in isolation in Sydney until July 6 and be tested at least two more times.

The NSW parliament was on Thursday declared a potential exposure venue during one of the busiest weeks of the year - budget week - after Agriculture Minister Adam Marshall tested positive.

Australian Associated Press