The multi-day "protestival" will ramp up on Friday morning when participants attempt to occupy parts of Newcastle Harbour and the foreshore with a flotilla.
The event near the Port of Newcastle also includes live music and other activities to amplify a call to end the expansion of fossil fuel use.
Children are set to join the action as they rally outside Customs House for a School Strike for Climate before joining the harbourside festival later in the day.
Frankie Kelly, a 12-year-old primary school student, will participate in the weekend events.
"It is scary knowing that I am growing up into a world that is severely affected by climate change, especially when the government continues to approve new coal and gas projects," she said in a statement.
"But I feel a little bit better knowing there are people at the strike who will join us in fighting for climate justice."
Former federal environment minister and Midnight Oil frontman Peter Garrett will be part of the live music line-up.
The event follows a successful last-minute legal challenge by organisers Rising Tide to overturn a government-ordered "marine exclusion zone" that would have prevented the protesters from entering the water.
The Minn's government tried to shut down The People's Blockade but the Supreme Court ruled the government's exclusion zone notice had excluded the public from the water and was beyond the powers of the Marine Safety Act.— RisingTideAustralia (@RisingTideAus) Our 50-hour flotilla will commence tomorrow! pic.twitter.com/x2yJ5MOr2tNovember 21, 2024
As a result, the group said protesters could peacefully enter the water off Horseshoe Beach, near the mouth of the harbour, to conduct a flotilla without impeding the nearby shipping channel.
Transport for NSW issued the exclusion order a week earlier, including a maximum $1100 fine for anyone entering the water and $3300 fine for anyone in the vicinity who failed to comply with directions.
Rising Tide lawyer Felicity Graham successfully argued in the NSW Supreme Court the purpose of such zones was to protect public safety during "special events" on waterways, not prevent them from happening.
NSW Police have flagged safety concerns about the planned coal protest at Newcastle Harbour. (Michael Gorton/AAP PHOTOS)
During the hearing, protest organiser Alexa Stuart agreed Rising Tide promoted civil disobedience and said some of those at the event might break the law to draw more publicity to the cause.
"I would say it is likely," she said.
Police have repeatedly flagged concerns with the safety of the event, citing a similar action in 2023 that resulted in the arrests of nine people who refused to exit the water at an agreed time.
They were successful in an earlier court application to have the planned protest declared unlawful, leaving participants liable to arrest if they block port or other essential infrastructure.
Rising Tide is calling for an end to new coal and gas approvals, and the imposition of a 78 per cent tax on coal and gas exports to help fund the energy transition.
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