NSW Police late on Christmas Eve moved to ban protest rallies from key metropolitan areas in Sydney after legislation was passed earlier the same morning to allow the action following declared terrorist incidents.
Premier Chris Minns said he backed the police commissioner's decision "100 per cent" because the government could not allow a situation where "mass protests rip apart our social cohesion".
"I know that they're extraordinary powers," he told reporters at a Christmas lunch event on Thursday.
"We believe they are absolutely essential in keeping order and peace during this Christmas period and through the summer."
The laws grant the police commissioner the power to temporarily declare public areas "restricted" from approved assemblies after a designated terror event, such as the Bondi attack that left 15 innocent people dead.
The current declaration restricts public assemblies in Sydney's southwest, northwest and central metropolitan areas for 14 days, a measure that can be extended fortnightly for up to three months.
Any public assembly in that time will be taken to be unauthorised, leaving people liable for arrest if they are found to have obstructed traffic or pedestrians.
Police will also have the authority to remove face coverings worn by people suspected of committing offences.
The premier said it was "incredibly important" to act fast, citing a promised peaceful vigil by protesters that he said channelled hate speech.
Participants used slogans including "globalise the intifada", commonly heard at pro-Palestinian rallies but a phrase the state government plans to outlaw in the coming year.
"Our number-one obligation right now and forever is to keep the public safe, and we're going to take whatever steps and whatever actions we believe are necessary to do that," Mr Minns said.
Police Commissioner Mal Lanyon said the anti-protest declaration was designed to give officers the powers to ensure community safety.
"The tragic events at Bondi Beach have left a profound impact on our community and reaffirmed the urgent need for stronger safeguards to reduce fear and increase safety," he said.
"It's not a time for large public assemblies and division."
Civil liberties groups have labelled the anti-protest laws draconian and said they infringe on the right to assembly, with a High Court fight planned.
Former NSW Supreme Court judge Anthony Whealy, who presided over Australia's largest terrorism trial, said the legislation could be liable to challenges on multiple grounds and it might not be the calming influence intended.
The laws could be seen to be aimed at shutting down pro-Palestinian protests or criticism of Israel's behaviour in the Gaza war, he told AAP.
"It may even increase anti-Semitism or at least harden attitudes towards Israel and its activities," he said.
"If so, it is unlikely to contribute to the Jewish community feeling more safe."
Several prominent Jewish leaders have hailed Mr Minns' crackdown on protests and hate speech following the Bondi massacre of December 14, when two Islamic State-inspired gunmen opened fire on Hanukkah celebrations.
Meanwhile, Indigenous groups have raised concerns an extension of the police anti-protest designation could render "invasion day" protests on January 26 unlawful.
Mr Minns said the assemblies could take place, although he drew a distinction between static rallies and marches through the city.