More than 100,000 people braved heavy rain for a pro-Palestine protest at the landmark bridge on Sunday and similar rallies in Melbourne and Adelaide.
Dubbed the March for Humanity, it aimed to highlight what the United Nations has described as the "worst-case scenario of famine" and the 22-month-long Israeli offensive on the blockaded enclave.
But the organising Palestine Action Group said it had bigger plans in store with a national march slated for August 24.
Groups in Melbourne, Perth, Canberra and Adelaide will join the mass demonstration, and spokesperson Josh Lees forecast many more protests in regional towns.
"We want to build on this massive momentum that we have now coming out of the massive March for Humanity," he said.
"There are pro-Palestine movements going on, protests against genocide taking place in every town and city in Australia."
NSW Premier Chris Minns was adamant he did not misread community sentiment in trying to stop the mass demonstration from going ahead.
Organisers estimate about 300,000 people attended Sunday's march, while police put the figure around 90,000.
"We can't just knock out the bridge every weekend. There can be a demonstration every weekend ... no one should assume it's open season on the bridge," the premier said.
There were no plans to march over the Harbour Bridge again any time soon, Mr Lees said.
Mr Minns said the government would closely study the Supreme Court ruling that allowed the mass rally to go ahead the following day, to see if it set a precedent.
He thought police "were on firm ground" rejecting the protesters' application but did not rule out any measures to set limits for how the bridge could be used in future.
Mr Lees said it was "astonishing" the government could view Sunday's "inspiring display of humanity" and think it should be prevented from happening again.
Prime Minister Anthony Albanese said he was not surprised by the monumental turnout in Sydney.
"(Australians) want to show their concern at people being deprived of food and water and essential services," he said.
Gaza's population of 2.1 million people is projected to face high levels of acute food insecurity, including one million people who face emergency levels, according to the United Nations.
Several Minns government MPs and Sydney's lord mayor took part in the march and Mr Minns struck a conciliatory tone, praising demonstrators for the peaceful nature of the rally.
Federal Labor MP Ed Husic said voters had sent a strong message to politicians
"There was a lot of middle Australia there and that's something that can't be ignored," he told ABC Radio.
NSW Police praised the behaviour of the protesters but forced them to turn around mid-march, citing the large number of people taking part.
Police did not make any arrests, and organisers and participants have questioned their characterisation of the protest as unsafe or chaotic.
Federal Opposition Leader Sussan Ley questioned "the shutting down of a major city" for an overseas conflict but conceded the huge community concern around events in Gaza.
"Ultimately Australians do want to see Gazans fed, they want to see the Israeli hostages released (and) they want to see the war end," she said.
Israel's military campaign began after militant group Hamas attacked Israel on October 7, 2023, killing 1200 people and taking about 250 hostages.
The ensuing retaliatory bombardment and blockade of Gaza have killed more than 60,000 people, according to local health authorities.
The federal government on Monday announced an additional $20 million to support aid organisations in delivering food, medical supplies and other lifesaving support in Gaza.
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