Gladys Berejiklian has been joined by other Australian political leaders, such as Victorian Premier Daniel Andrews, who said the protestors were "selfish" and they had put others in danger.

The protestors defied stay-at-home orders and many were not adhering to social distancing requirements during Saturday's protest in the Sydney CBD, nor wearing masks. And there was a significant degree of unrest.

There were protests in other Australian cities, including locked-down Melbourne where flares were set off and several protestors arrested.

Sydney Police charged 57 people and issued 90 infringement notices, while police strike force 'Seasoned' is scouring CCTV and social media footage to hunt down other participants.

Two men are accused by police, among other offences, of striking a police horse.

"It broke my heart," Premier Berejiklian said on Sunday.

"Millions and millions of people across our state are doing the right thing and it just broke my heart that people had such a disregard for their fellow citizens.

"I just ask everybody to think about that. Each of those people who protested illegally, I'm sure have loved ones.

"They are going to go home and risk passing that virus on to the most closest people to them."

The state has recorded 141 locally acquired cases and 38 of them were infectious while in the community.

There were two deaths overnight taking the current outbreak's total to eight.

They were an inner city Sydney woman in her late 30s with no known health complications and a woman in her 70s from south-west Sydney.

COVID-19 NEWS:

The premier acknowledged frustration in the community, especially with loss of income, but she is concerned that "events like that can cause those super-spreading events".

"I appreciate that some people are feeling frustrated, but that is no reason, absolutely no reason, for those actions yesterday. No excuse, I'm sorry," Ms Berejiklian said.

"We don't want a setback, and yesterday could have been a setback. Time will tell."

The Victorian Premier said on Sunday that everyone was entitled to an opinion, but not if it put people in danger.

"Ultimately, selfish, selfish behaviour that puts many, many other people in real danger," Mr Andrews said.

"I just hope that it doesn't have an impact on cases and doesn't have an impact on the sort of rules that we all have to live under."

There are currently 141 COVID-19 cases in Sydney hospitals. Of these, 43 people are in intensive care, 18 of whom require ventilation.

NSW Health's Dr Jeremy McAnulty said the Delta strain was affecting all ages.

Of the people in intensive care, he said one was teenager, seven people were in their 20s, three in their 30s, 14 in their 50s, 12 in their 60s and six in their 70s.

"So this is affecting people of all ages with very serious disease," he said.

"All but one are vaccinated. One person has just received one dose of vaccine."

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