The iconic Sydney Harbour Bridge will be the site of a major protest against the war in Gaza with politicians, union groups and humanitarian advocates expected to participate.

The bridge will be closed from 11.30am to at least 4pm on Sunday due to the protest, Transport for NSW said.

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

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Organisers expect tens of thousands to march from the Sydney CBD across the bridge to North Sydney, but numbers could be affected by forecast 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.