South Western Sydney Primary Health Network chief executive Keith McDonald is urging residents to listen to healthcare leaders and follow the health advice.
"Please take the health advice from public health officials seriously. Doctors have your health and best interests at heart," he said.
"Limit your interactions to your immediate household and please consider carefully what is an essential activity, and what isn't."
As a result of the growing number of infectious cases in the community and unlinked cases of community transmission, COVID-19 restrictions will be tightened across Greater Sydney.
Exercise groups will shrink from a maximum of 10 to two for parts of greater Sydney from 5pm on Friday. Car pools have also been ruled out and from Sunday funerals will drop to 10 people.
NSW recorded 44 cases to 8pm on Thursday night, with 29 circulating while infectious. Of the new cases, 21 are from south-west Sydney.
The Australian Medical Association (NSW) and Primary Health Networks have joined together to call on Greater Sydney residents to take the lockdown restrictions seriously.
NSW Australian Medical Association (AMA) president Danielle McMullen said all of Greater Sydney needs to be vigilant
"We need to get the lockdown right and stop acting like it's 'lockdown-lite'," Dr McMullen said.
"The Delta-variant is COVID on caffeine - it's more contagious and it's potentially very severe.
"It has quickly moved from Bondi and now we're seeing areas of concern in western Sydney - but Killara, Katoomba, or Kogarah could be next.
"We need to support each other - no matter where you live - and ensure we're doing everything we can to protect ourselves and protect our communities."
Professor Brad Frankum, a Narellan immunologist and former AMA (NSW) president, said there are currently 10 patients admitted to hospital under age 35 with COVID-19.
"This is serious. Regardless of whether you are over-65 or in your 20s, the effects of this disease can be devastating," he said.