Labor is facing internal accusations of betraying its own values as fast-tracked moves to curb protests face a constitutional challenge from a disparate coalition of civil groups.
Measures to limit demonstrations, stem hate speech and crack down on gun ownership are expected to pass the NSW parliament on Tuesday in quick response to the Bondi massacre of December 14.
The state's lower house on Monday night overwhelmingly backed the sweeping changes, led by Labor and supported by the Liberals.
Under the planned changes, a terrorist attack designation would give police powers to reject protests for an initial 14 days and up to three months.
But that measure was branded undemocratic and unconstitutional by a group mobilising thousands of people weekly in Sydney's city streets.
"The Minns government is seeking to introduce laws that will represent the single most aggressive assault on our civil liberties in living memory," solicitor Nick Hanna, who will be representing the Palestine Action Group, told reporters.
Law reform was needed following the Bondi attack, during which 15 people were killed by two radicalised gunmen, Mr Hanna added.
But the protest changes were a knee-jerk attempt at politicising a tragedy and taking away basic democratic rights.
Mr Hanna said the constitutional challenge to the protest ban would most likely be launched in January.
Premier Chris Minns has directly linked pro-Palestine protests to the sowing of anti-Semitic rhetoric, which he said could develop into violence by "unleashing forces that the organisers of the protests can't control".
But the protest crackdown championed by the premier represented a shameful departure from Labor beliefs, senior left-wing party figure Peter Moss said.
"This is a betrayal of Labor values, a betrayal of our hard-won democratic rights, and a betrayal by Chris Minns of his own colleagues," the Labor National Policy Forum member and convenor of Labor Friends of Palestine said.
"These laws are not about saving lives."
Several outspoken Labor MPs who broke ranks with the premier over pro-Palestinian protests and marched across the Harbour Bridge in solidarity in August were also present at the press conference.
But they are likely to vote for the laws under party rules forbidding MPs from crossing the floor.
The laws are expected to swiftly pass through the upper house on late Tuesday or early Wednesday despite the Greens wanting to split gun reforms from the protest crackdown and Shooters, Fishers and Farmers MPs complaining their voters are being scapegoated.
Parliament was recalled to debate the laws after the Bondi massacre, which has highlighted flaws in rules surrounding access to high-powered rifles.
Labor's bill has caused a split in the coalition, with Nationals MPs and one Liberal from a regional electorate opposing the changes due to concerns about the firearms restrictions, which cap the number of guns people can own to four and limit magazine capacities.
Premier Chris Minns previously said the extraordinary gun and protest measures were necessary to restore a sense of safety after the attack on Jewish residents.
"We can't pretend that the world is the same as it was before that terrorist incident on Sunday," he said.
"My government's number-one priority is to keep the people of NSW safe and that means making these changes."
A poll out on Tuesday suggested three in every four Australians back toughening gun laws.
The Resolve poll of 1010 people conducted after the mass shooting found similar support among voters for Labor (80 per cent), the coalition (78 per cent) and One Nation (82 per cent).
