The controversial curbs on protests were brought in after December 14, when 15 people were killed as a father-and-son duo of gunmen opened fire on a Hanukkah celebration.
The new laws allow the police commissioner to suspend the public assembly regime for up to three months after a terror attack, on community safety grounds.
A coalition of Jewish, Palestinian and Indigenous activists appeared at the NSW Court of Appeal on Thursday as they sought to have the laws struck out.
Their barrister, David Hume SC, said protest was "the oldest and most orthodox form of public expression of political dissent in a representative democracy".
The laws burdened the community's right to political expression through public assemblies, he told a panel of three judges.
The new laws were a worse alternative to the previous legislation and were also overly broad, he told the court.
"They use a sledgehammer to seek to crack a nut," Mr Hume argued.
Under standard conditions, protesters can avoid potential prosecution for obstructing roadways or access to key infrastructure by providing police early notice about a public assembly.
That authorisation can be overturned by the NSW Supreme Court if it agrees with police about safety concerns.
Protesters can also seek court approval where police object to a short-notice rally.
That regime worked and promoted safe protesting, Mr Hume said.
Instead, the new laws restricted all protests on the basis of the police commissioner's view of community safety, blocking rallies which had none of those risks, he argued.
The laws also gave police broad and uncontrollable powers to move participants on, he said.
Premier Chris Minns has publicly defended the expanded police powers, saying they were "absolutely essential in keeping order and peace" after the deadly massacre at Bondi.
In court, the NSW government defended the constitutionality of the laws while arguing the activists' case was no longer valid.
The case should be dismissed because protest restrictions had been eased on February 17 and the activists were no longer affected by them, barrister Brendan Lim SC said.
Before the hearing on Thursday, around 40 protesters gathered outside court where impassioned speeches were made against the state Labor government and its laws.
Australians had witnessed the police brutality at Sydney protests against the Australian visit of Israeli President Isaac Herzog, said Wiradjuri woman Latoya Aroha Rule.
"Our right to protest is not negotiable," she said reading a statement from Indigenous activist Elizabeth Jarrett who is one of those leading the lawsuit.
"Minns must resign - his anti-protest laws need to be ripped up."
The activists' solicitor Nick Hanna commended his "very brave" clients in their fight to preserve a fundamental democratic right.
"It's difficult to think of a case that is more consequential for political freedoms in this state," he said.
"It's a case that should be supported by everyone in this state regardless of your political ideology because it will benefit and protect all of you."
The hearing continues.
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