As the Covid outbreak in Sydney worsens, experts are beginning to believe that achieving zero cases may be impossible and that the city may need to be put on lockdown until Christmas.

Despite a month-long lockdown, the number of cases in NSW has continued to rise, reaching 145 today, the second-worst daily figure in the outbreak.

Two additional people have died of Covid, according to the state, a man and a lady in their 80s. This puts the total number of people killed in the current epidemic to ten.

Due to the stiffer limitations imposed a week ago, NSW Premier Gladys Berejiklian had hoped to see a drop in cases over the weekend and early this week, but this has yet to happen.

Experts point out that the state's five-day average jumped to 135 instances on Sunday, up from a high of 163 cases on Saturday and 144 cases on Sunday.

Professor Nancy Baxter, a clinical epidemiologist at Melbourne University, believes Greater Sydney may not be able to achieve zero cases through the lockdown.

"I think we are all surprised at how infectious Delta is, I think that's what the real game-changer is."

It's unclear why the number of instances hasn't decreased yet, but Baxter said NSW officials had implemented steps gradually.

"Hopefully, we'll start to see more of an effect now; I think that's what we're all hoping for."

"While there has been talking of NSW "living with the virus," according to Baxter, "no one is even thinking living with it until people are vaccinated because living with it means a lot of people will die with it."

This means Sydney will be on lockdown until enough people have been vaccinated, which might take until the holidays.

"Because lockdown restrictions haven't gotten the virus under control to the extent we want it under control," Baxter added, "that's a possible scenario."

"It's difficult to imagine that weaker constraints will keep things hidden. If it's not under control during the lockdown, it'll detonate when we get out of lockdown."

Professor Adrian Esterman, an epidemiologist at the University of South Australia, warned earlier today that the state's lockdown plan "is simply not working"

The five-day moving average, according to Esterman, "is still going up" and the outbreak should have "reached its peak and started coming down"

"If the lockdown was hard enough [we would have seen that already]," he told news.com.au.

"Clearly, it is either not hard enough, or there are too many Sydneysiders not complying with the lockdown."

On Saturday, 163 new coronavirus cases were reported in NSW, and 141 new coronavirus cases were reported on Sunday. Today's number brought the total number of days with over 100 new local cases to six.

A total of 76 persons were infected and traveling around the community, with 51 staying in the community the entire period they were contagious and 25 staying in the community for part of the time.

The number of cases mingling in the community while infectious has been frequently highlighted by health authorities as a major source of concern.

'Some options may change'

Health officials are considering limiting travel in high-risk suburbs even further while allowing more freedom in suburbs with few transmissions.

Today, Berejiklian said, "Some settings might change,"

"In some areas, we may need to push harder, while in others, we may need to relax some settings." Please be assured that our government is continuously considering the greatest solutions available."

Berejiklian hinted that the lockdown in Sydney might be extended past Friday. The announcement is scheduled to be made by the end of the week.

"We hope to provide announcement or updates to the community in the next few days," Berejiklian added.

"Our mission is to keep the community as safe as possible but also make sure the community can live as freely as we can."

Dr. Kerry Chant, NSW's chief health officer, seems to imply that the state would not be coming out of lockdown any time soon.

When a reporter asked if the lockdown would have to last until the state had zero community cases or 80 percent immunization, she said, "The Premier stated that those discussions are ongoing concerning the approach... But I believe we've discovered that with the Delta variation, you don't have much leeway.

"It's such a highly infectious strain of the virus, and because we're dealing with an issue, whenever we get to a case in a family, the family has already been infected, or will become positive in the next few days." It does not have a grace period.

"With the previous strains, we could get to people early enough and so I think with that challenge, we need to ensure that our approach aligns with that."

More protests are expected

On Saturday, tens of thousands of anti-lockdown protestors poured on the CBD, raising worries of a super spreading incident.

State leaders, including the Premier and top cops, have expressed their displeasure with the gathering.

More protests are expected on Saturday, according to NSW Police Deputy Commissioner Gary Worboys.

"There are various debates... "At the moment, there's some information on the internet about possible protests on Saturday," he stated.

"Can I just issue a warning to everyone right now, [it] will be heavily policed." We'll be on the ground very soon, and you'll be arrested.

"The community has spoken about that behavior, the Premier has spoken about that behavior, and it won't be tolerated."