A leading epidemiologist has warned Sydney's coronavirus lockdown could last beyond August.
Professor Marylouise McLaws, who is an epidemiologist at the University of New South Wales and a World Health Organisation adviser, told Channel Nine's Weekend Today it could be weeks before Sydney exited lockdown.
She said there were "several indicators" that show a success in containing the virus.
"One of the most important ones is the proportion of people who are found positive and have not been in isolation. And at the moment, that's been very high," Prof McLaws said.
The epidemiologist predicted it would take "at least a month" to bring down the number of infections and those who have been circulating in the community.
"Then you'll need another two (weeks) to ensure you've got it right," Prof McLaws said.
She added: "This is why it's so important to do early lockdowns because then you don't have so much virus to then have to clamp down and it stops people from moving."
NSW Premier Gladys Berejiklian hinted on Friday it was becoming increasingly unlikely lockdown would end as planned on July 16.
The state announced 44 local Covid infections on the same day, which is the highest daily total since the outbreak began on June 16.
Of those new cases recorded to 8pm on Thursday, 29 were partly or fully in the community while infectious.
"We can't see that continue," Ms Berejiklian said.
"When you see the fact that the numbers of cases are going up in the community substantially, we are extremely concerned that we need to turn the tide.
"This is the opposite of where we need or want the numbers to trend."
Tougher restrictions for Sydney residents
Sydneysiders woke up to its first full day of further restrictions on Saturday, introduced to slow the highly-infectious Delta variant.
The new rules kicked in from 5pm on Friday and included:
Exercise in groups of two only - households however are allowed to exercise together
Ten-kilometre limit for exercise
No carpooling with people from outside your household
Funerals limited to 10 people only
One person from the home at a time is allowed to shop for essentials
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