Protesters marching across the iconic Sydney Harbour Bridge have been urged by NSW Police to stop marching.

The major protest against the war in Gaza with politicians, union groups and humanitarian advocates was given the green light to proceed on Sunday.

The bridge was scheduled to be closed from 11.30am to at least 4pm due to the protest.

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According to the initial plan, protesters were to walk northbound from the Wynyard end of the bridge and disperse in North Sydney.

However, due to public safety concerns and the prevailing weather conditions, NSW Police issued an updated statement on Sunday announcing that protesters would be permitted to return southbound across the bridge to the Sydney CBD.

A geo-location text was then sent out at 3pm, urging protesters to stop the march.

“In consultation with the organisers, the march needs to stop due to public safety and await further instructions,” the text said.

“We are asking that everyone stops walking north. As soon as the march has stopped, we will look at turning everyone around back towards the city BUT it needs to be done in a controlled way in stages to keep everyone safe.”

The safety of the public and police has always been a top priority, Operation Commander, Acting Assistant Commissioner Adam Johnson said earlier on Sunday.

Before the message calling for the protest to stop was sent, part of the protest had been re-routed back over the bridge.

“Due to the risk of a potential crowd crush scenario at the train station, we will now provide the ... option of allowing protesters to walk back across the bridge and disperse in the CBD,” Johnson said.

“This means the bridge will remain closed for a longer period than originally planned, until the operation concludes.”

Rally organiser Palestine Action Group intends to draw attention to what the United Nations has described as “worsening famine conditions” in Gaza.

Organisers expected tens of thousands to march from the Sydney CBD across the bridge to North Sydney, but numbers may have been affected by heavy rain.

NSW Police on Saturday sought an order to prohibit the protest but Supreme Court Justice Belinda Rigg rejected the application, meaning protesters will have immunity and protections from offences such as blocking or obstructing traffic or pedestrians.

A large police presence has been mobilised to ensure safety, with the bridge to be closed to motorists for most of Sunday.

“We ask that all the participants who are coming into the city to take part in this public assembly, listen to police, be respectful, understand that there will be large crowds,” acting Deputy Commissioner Peter McKenna said.

“We will have police right along the route and we’ll be making sure this is done as safely and peacefully as possible.”

Police warn they will take swift action against anyone who seeks to hijack the peaceful protest.

Several Labor MPs will defy Premier Chris Minns, joining the march alongside multiple Greens and independent colleagues.

In support of the demonstration, the Jewish Council of Australia described the occasion as “momentous”.

“We stand with and join those marching across the bridge and call for immediate action to stop the Gaza genocide,” executive officer Max Kaiser said in a statement.

Executive Council of Australian Jewry CEO Alex Ryvchin said there was “a lot of dismay in the community and wider society that a single judge has overruled a decision of the police and the elected government made in the interests of public safety”.

Similar demonstrations are planned on Sunday in Melbourne and Adelaide.

More than 60,000 Palestinians have been killed in the war in Gaza, according to local health authorities, while the United Nations says dozens of people have died in recent weeks due to starvation.

Israel’s military campaign began after militant group Hamas attacked Israel on October 7, 2023, killing 1200 people and taking more than 251 hostages.