A teenager is being treated in an intensive care unit after contracting Covid-19 during the outbreak in NSW.
The teen was one of 16 people who were treated in the ICU for the coronavirus disease.
"Of the 16 people in the ICU, one is in their teens," chief health officer Kerry Chant said on Saturday.
Dr Chant said the case is not being ventilated.
"Obviously we don't release information about individual cases, but I think it is a salient lesson that Covid can impact across all age groups and I'm not aware of any other specifics around that case," she said.
Young people are being urged to abide by New South Wales' tight lockdown restrictions, as health authorities reveal a person in their 20s is currently in intensive care and on a ventilator after a Covid-19 diagnosis.
NSW Premier Gladys Berejiklian said officials had seen an unusual amount of young people with serious symptoms from Covid-19 during the current outbreak.
"We have a number of young people in ICU at the moment and that is a phenomena we have not seen before in terms of the broader population," she said.
Out of the 16 people in the ICU, there were one each of people in their twenties, thirties, forties and eighties.
There were three people in their fifties, six people in their sixties and two people in their seventies among the ICU patients as well.
"Covid cannot affect people if you do not come into contact with them … That is the basis of the stay at home orders."
Five of the people were on ventilators.
Since the pandemic hit Australian shores in March last year, the majority of all infections have been in people aged between 20 to 50 years, according to the Commonwealth health department.
The number of cases was the highest in people in their twenties.
Lockdown rules tightened
Berejiklian announced tougher restrictions this afternoon as she warned the state wouldn't end lockdown until cases "get to zero or close to zero".
She said today's record number was "the opposite of where we need or want the numbers to trend".
"No state or nation or any country on the planet can live with the Delta variant when our vaccination rates are so low," she said.
"If we choose to live with this while the rates of vaccinations are at 9 per cent, we will see thousands and thousands of hospitalisations and deaths."
That means "until we get to zero or close to zero, we cannot ease restrictions", and "in fact, based on the health advice, NSW will be further tightening restrictions in those areas that already have stay-at-home orders".
Outdoor exercise has been reduced from 10 people to two people, and only within 10km of home.
Only one person is allowed to leave home for essential shopping except under "exceptional circumstances".
Funerals will also be reduced to 10 people.
The new rules will take effect from 5pm today.
Berejiklian said NSW might not exit lockdown next Friday.
"NSW is facing the biggest challenge we have faced since the pandemic started and I don't say that lightly," she said.
"And unless there is a dramatic change, unless there is a dramatic turnaround in the numbers, I can't see how we would be in a position to ease restrictions by next Friday, and that is why all of us need to work together."